T M 1 1 - 5 8 9 5 - 1 0 1 2 - 1 0

W A R N I N G

W A R N I N GDANGEROUS VOLTAGES are present during the preparation of the test circuits6-20. Turn all power switches off before constructing them test circuits. Failurecould result in serious injury or death.

TM 11-5895-1012-10

TECHNICAL MANUAL

No. 11-5895-1012-10DEPARTMENT OF THE ARMY

WASHINGTON, DC, 4 January 1978

OPERATOR'S MANUAL

TECHNICAL CONTROL FACILITY

(GENERAL)

REPORTING OF ERRORSYou can improve this manual by recommending improvements using DA Form 2028-2 (Test) locatedin the back of the manual. Simply tear out the self-addressed form, fill it out as shown on the sample,fold it where shown,, and drop it in the mail.If there are no blank DA Forms 20-28-2 (Test) forms in the back of the manual, use the standard DAFor 20-28 (Recommended Changes to Publications and Blank Forms) and forward to Commander,US Army Electronics Command, ATTN: DRSEL-MA-Q, Fort Monmouth, New Jersey 07703.In either case a reply will be furnished direct to you.

TABLE OF CONTENTSParagraph Page

CHAPTERCHAPTERSection

CHAPTERSection

CHAPTERSection

1-1. , 1-1

Section

VIII.CHAPTERCHAPTERAPPENDIXAPPENDIXINDEX

Number

2-1,2-2,2-3,2-4,2-6,2-6,2-7,2-81,2-82,2-83,2-84,2-85,2-9,2-10,2-11,

1.2.I.

II.III.IV.

3.I.

II.III.

4.I.

II.III.IV.V.

VI.VII.

5.6.A.B.

. . . . . .

INTRODUCTIONDESCRIPTION OF TECHNICAL CONTROL FACILITYGeneral... . . . . . . . . . . . . . . . . . . . . . .System Service Interfaces, and Types of Signals . . . . .The Technical Control Facility . . . . . . . . . . . .Representative TCF Equipment . . . . . . . . . .EXAMPLES OF OPERATIONAL TCF'SPirmasens . . . . . . . . . . . . . . . . . . . . .B e r l i n . . . . . . . . . . . . . . . . . . . . . . . .Pentagon . . . . . . . . . . . . . . . . . . . .TCF OPERATIONSOperation Practices and Methods. . . . . . .circuit Rerouting . . . . . . . . .Patching Operations. . . . . . . . . . . . . . .Failures and Fault Isolation . . . . . . . . . . .Performance Standards and Test Measurements .Circuit Performance and Quality Control Testing .Implementation of Communications Services RequirementsAcceptability of New Equipment . . . .STATION MAINTENANCE .TEST PROCEDURES... . . . . . . . . . . .REFERENCES.. .ABBREVIATIONS.. . . .. ... . . . . .. . . : .

2-1. , 2-12-7. , 2-4

2-15. , 2-112-30. , 2-34

3-1. , 3-13-4. , 3-33-7. , 3-6

. . .

LIST OF ILLUSTRATIONSTitle

4-1. , 4-14-13. , 4-44-17. , 4-64-22. , 4-124-39. , 4-314-46. , 4-394-56. , 4-464-60. , 4-495-1. , 5-16-1. , 6-1

A-1B-1

Example of a world-wide common user network . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..Interconnection of communications facilities, simplified diagram . . . . . . . . . . . . . . . . . . . .Subsystem interface with the DCS. . . . . . . . . . . . . . . . . .AUTODIN Interface with the DCS .......... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Technical Control Facility, interface diagram .Technical Control Facility, configuration block diagram . . : . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . .Technical Control Facility, typical floor plan . . . . . . . .Typical voice frequency circuits (Sheet 1 of 5)....... . . . . ... .. . .. ..... : .. ... :Typical voice frequency circuits (Sheet 2 of 5)Typical voice frequency circuits (sheet 3 of 5) . ...... . . ..... .. -- ..... .. . . . ... . .. . ...Typical voice frequency circuits (sheet 4 of 5) . . . . . . . . .Typical voice frequency circuits (sheet 5 of 5) . . . . . . . . . . . . . . . . ... .. .......... ......... : .Standard dc/data access circuits.. . . . . . . . . . . . . . . . . . .Double bus arrangement and automatic transfer panel, wiring diagram.:. . . . . .... . . .Uninterruptible power supply in standby condition. . . . . . . . . . . . . . . ......... . . . . . . . . . . . . . . . . . . . , . . . .

Index 1

Page2-52-72-92-102-132-142-162-172-182-202-212-232-252-292-31

i

TM 11-5895-1012-10

Number2-122-132-142-162-162-172-182-192-202-212-222-232-242-252-262-273-13-23-33-44-14-24-34-44-64-64-714-724-814-824-834-914-924-104-114-124-134-1414-1424-1436-16-26-36-46-56-66-76-86-96-106-116-126-136-146-156-166-176-186-196-20FO-1FO-2

Title

Uninterruptible power supply in on-line condition. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .ADMSC uninterruptible power system . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Solid state uninterruptible power system, simplified block d&gram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Voice frequency primary or equal level and signaling patch panels front view . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .E&M patch panel, interconnection diagram. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Two-wire voice frequency primary patch panel, interconnection diagram. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Dc patch panel, low level receive, interconnection diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Dc patch panel, low level transmit, interconnection diagram. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .DC patch panel (transmit or receive) with cut keys and lamps, front view . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Typical miscellaneous patch panel, front view . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Miscellaneous/interbay patch panel, interconnection diagram. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Voice frequency interbay patch panel, interconnection diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Typical series and parallel interbay trunking systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .DC interbay patch panel with 48 lamps, front view . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .DC interbay patch panel with 48 lamps, interconnection diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Miscellaneous patch panel with 10 lamps, interconnection diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Red digital patch bay (typical), front view . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Red digital test bay (typical), front view . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Red vf test bay (typical). front view . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Quality assurance test center (Pentagon) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Transfer of circuit to spare multiplex channel at the equal level patch panel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Transfer of circuit to spare cable circuit at the primary patch panel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Substitution of line conditioning equipment using the equal level and primary patch panels . . . . . . . . . . . . . . . . . . . . .Transfer of a Dc circuit to a spare VFCT channel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Transfer of a Dc circuit to a spare digital line interface unit (DLIU).. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Transfer of a Dc circuit to a spare cable pair. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Noise burst on multiplexed through circuit, fault isolation flow chart (sheet 1 of 2) . . . . . . . . . . . . . . . . . . . . . . . . . . . .Noise burst on multiplexed through circuit, fault isolation flow chart (sheet 2 of 2). . . . . . . . . . . . . . . . . . . . . . . . . . . .Noise burst on a local subscriber circuit, fault isolation flow chart (sheet 1 of 3) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Noise burst on local subscriber circuit, fault isolation flow chart (sheet 2 of 3) . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Noise burst on local subscriber circuit, fault isolation flow chart (sheet 3 of 3). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Vf subscriber circuit loop-back method, fault isolation flow chart (sheet 1 of 2). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Vf subscriber circuit loop-back method, fault isolation flow chart (sheet 2 of 2) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Relative envelop delay vs frequency limits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Sample distortion trend analysis chart. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Sample noise level trend analysis chart . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Sample number of outages trend analysis chart. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Sample voice frequency circuit configuration connection diagram (sheet 1 of 3). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Sample voice frequency circuit configuration connection diagram (sheet 2 of 3). . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Sample voice frequency circuit configuration connection diagram (sheet 3 of 3) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Idle channel (residual) noise test.Frequency response test. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Envelope delay distortion test. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Audio frequency test. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Longitudinal balance input test. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Longitudinal balance output test. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Single tone interface test. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Conversion dBm to dBrnc0. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Impulse noise test. . . . . . . . . . . . . . . . . . . :Terminal impedance test for transmit circuit. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Terminal impedance test for receive circuit. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Harmonic distortion test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Composite signal transmission level test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Phase jitter testing using an oscilloscope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Phase jitter testing using a phase jitter meter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Station to station signaling test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .In-stations signaling test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Net loss variation test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Station to station total peak and average bias telegraph distortion test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .In-station total peak and average bias telegraph distortion test. . . . . . . . . . . . . . . . . . . . . . . . . . . . . Located in back of manualSimplified power distribution system. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Located in back of manualVf primary or equal level patch panel, interconnection diagram. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Located in back of manualPrimary Dc patch panel, interconnection diagram. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Located in back of manualDc patch panel (receive) with cut keys and lamps, interconnection diagram. . . . . . . . . . . . . . . . . . Located in back of manualDc path panel (transmit) with cut keys and lamps, interconnection diagram . . . . . . . . . . . . . . . . . . . Located in back of manualTCF Pirmasens, signal diagram. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Located in back of manual

Page2-312-322-342-392-402-412-432-442-462-472-482-492-502-512-522-533-83-83-93-104-84-94-104-114-134-144-214-224-234-244-254-264-274-384-444-444-454-504-504-516-36-46-56-76-96-106-116-116-136-146-156-186-176-186-196-216-226-226-236-24

FO-3FO-4FO-5FO-6

ii

NumberFO-7FO-8FO-9FO-10FO-11FO-12FO-13FO-14FO-15FO-16

TitleTCF Pirmasens, floor plan . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .TCF Berlin, signal diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .TCF Berlin, floor plan . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .TCF Pentagon, signal diagram. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .TCF Pentagon, floor plan. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .TCF Pentagon, QA test center floor plan . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Typical black digital circuit IDF connection diagram. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Universal digital patch panel, interconnection diagram. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Universal digital patch panel black send circuit strapping diagram. . . . . . . . . . . . . . . . . . . . . . . . . . . . .Universal digital patch panel black receive circuit strapping diagram . . . . . . . . . . . . . . . . . . . . . . . . . .

TM 11-5895-1012-10

PageLocated in back of manualLocated in back of manualLocated in back of manualLocated in back of manualLocated in back of manualLocated in back of manualLocated in back of manualLocated in back of manualLocated in back of manualLocated in back of manual

i i i

TM 11-5895-1012-10

CHAPTER 1

I N T R O D U C T I O N

1 - 1 . S c o p e

a. This technical manual describes a Technical Con-trol Facility (TCF) in general terms. It addresses thepurpose and function of the TCF; provides description

as to how a TCF will fit into the overall Defense Com-munications System (DCS) and the various types ofsignal which could appear at a TCF’s patch panels.

b. Included is a description of a typical TechnicalControl Facility; the off-site systems and equipmentwhich could interface with it as well as that equipmentmost usually located within the TCF, and a typical test

equipment load which is used for testing and trouble-shooting of communications circuits controlled by the

c. This technical manual also describes TCF opera-tions which include operational practices and meth-ods, circuit r&oration procedures, implementation ofcommunications services requirements, typical circuittroubleshooting procedures and testing of circuit per-

ment, refer to TM 740-90-1.

formance and quality.

1-2 . Indexes o f Publ i ca t ionsa. DA Pam 310-4. Refer to the latest issue of DA

Pam 310-4 to determine whether there are new edi-tions, changes or additional publications pertaining totheequipment.

b. DA Pam 310-7. Refer to DA Pam 310-7 to deter-mine whether there are modification work orders(MWO's) pertaining to the equipment.

1-3. Forms and Recordsa Reports of Maintenance and Unsatisfactory

Equipment. Maintenance forms, records, and reports

38-750.

P4610.19C, and DLAR 4500.15.

1 - 4 . A d m i n i s t r a t i v e S t o r a g e

1-5. Destruction of Army Material

1 - 6 . R e p o r t i n g E q u i p m e n t I m p r o v e m e n tR e c o m m e n d a t i o n s ( E I R )

1-7. Abbreviations

1 - 1

TM 11-5895-1012-10

C H A P T E R 2

D E S C R I P T I O N O F T E C H N I C A L C O N T R O L F A C I L I T Y

Sect ion I . GENERAL

2 - 1 . P u r p o s e

t restoration purposes, andfrom service for mainte-one of the tools available

2-2. Functions of a TCf

The major functions of personnel assigned to a DCSStation TCF are summarized as follows:a. Coordinate with the DCA Operations Control

transmission facilities and inter-pearing at the TCF, as well as the

extension of communications facilities provided by orusers of the DCS.

priori& and estab-direction, coordina-out-of-service trans-

the DCS station.

f. Exercise technical direction, coordination and su-pervision over activation, deactivation and rearrange-ment of transmission facilities in accordance with di-rections received.

g. Activate and deactivate traffic overload circuits.h. Report to DOCC and Operation and Maintenance

elements the status of transmission facilities for oper-ational direction and management.

i. Substitute equipment or circuits for maintenancepurposes or to isolate communications faults.

j. Performs required administration and recordkeeping.

2-3. General TCF Responsibil i t iesEach Technical Control Facility is responsible formaintaining continuity of service through effectiveoperation and maintenance of the DCS facilities with-in its operational area. This includes Patch and TestFacilities, and attended and unattended facilities.General functional responsibilities of TCF personnelinclude but are not limited to the following:

a. Restore or reroute disrupted circuits over avail-able facilities in accordance with the predeterminedrestoration priority. The technical control that firstbecomes aware of the outage is responsible for initiat-ing the restoration and follow through actions con-cerning the restoration, until such time as service is re-stored.

b. Report all information pertinent to an outage.c. When a disrupted segment of a circuit is on a dis-

rupted multiplexed group, coordinate with the FacilityControl Office (FCO) for that segment to determine ifthat segment of the multiplexed group is being re-stored.

d. Direct localization of troubles found or reported,when necessary refer troubles to the responsible office.

e. Provide progress reports, as required, in restora-tion activities.

f. Carry out technical control functions in locatingand clearing trouble in outside plant cable and facili-ties.

g. Conduct in-service quality control tests and assistin out-of-service testing and/or circuit realignment.

A. When a failure occurs on a multipoint circuit, de-termine and remove the affected segment. Restore thecircuit in accordance with priority assignment.

i. Review the temporary path change record regu

2-1

TM 11-5895-1012-10

larly. Take action to restore the circuit to its normalpath.

j. Notify the Circuit Control Office (CCO) when acircuit has been changed considerably or has been re-stored after prolonged outage so that the circuit can beretested end-to-end.

k. Respond to the operational direction and techni-cal supervision of higher level control offices.

l. Consult with the higher level control office beforetaking action that would disrupt service, except inemergency situations when the action cannot be de-ferred.

m. Prepare and forward reports in accordance withcurrent directives.

n. Establish written local operating procedures forcoordinating with commercial agencies, users, andother sections within the DCS Station.

o. Review circuit performance and initiate actionwith other stations to correct problems or unsatisfac-tory conditions. Refer conditions and problems beyondthe capability or outside the authority of the TCF tothe appropriate control center or operation and main-tenance activity with recommendations for resolution.

p. Arrange for coverage of partially attended orunattended stations when a need is anticipated orwhen an emergency or channel shortage arises.

q. Activate on-call or overload circuits.r. Coordinate and expedite activation of special cir-

cuits called for in special instructions.s. Maintain up-to-date contingency actions to be

taken in the event of significant communications fail-ure to ensure continuity of service.

t. Exercise extreme care so that service is not inad-vertently interrupted.

2 - 5 . A d d i t i o n a l R e s p o n s i b i l i t i e s

u. Report immediately all instances of negative oruntimely response from PTF’s, operation and mainte-nance activities, other TCF’s, or commercial agencies.

v. Make recommendations which would improve theTCF either as a facility or from an equipment stand-point.

w. Maintain and properly label equipment andpatch bays.

x. Assure that all technical controllers are trainedin authorized procedures and that these procedures arefollowed.

y. Maintain a current reference library readily ac-cessible to all technical controllers.

z. Publish and post notices concerning additions, de=letions, or changes in circuits; special tests on circuitsor equipment; changes in frequency assignments, etc.

2 - 4 . T C F R e s p o n s i b i l i t i e s t o S u b s c r i b e r so r U s e r s

A TCF which provides or user access to theDCS has additional responsibilities which must be sat-isfied. The service TCF personnel are responsible at all

stored orhave a circuit which

rerouted over new facilities tested from end-to-end.

f. Notiy the appropriate control officewill not be available at the time and date

tenance work, and other schedtions.

ties at the station as follows:a. Technical Control Facility. TCF

sponsible for:

(5) Radiated power.(6) Transmission levels.

c. Radio Receiver Station.

2 - 2

the identification of harmful in-

Assistance in the evaluation of jamming sig-

of incoming signals and makingons concerning frequency changes.

2 - 6 . S p e c i a l A s s i g n m e n t s

implementation of the overall control planrequires that certain TCF's be designated as FacilityControl Offices, Circuit Control Offices, and Interme-diate Control Offices (ICO). Control office designa-

Communicationsbased on recom-

and vary depending upon the length and complexity ofthe overall transmission facility, types of transmissionmedia involved as well as the communications andtesting facilities available. The responsibility for over-all service still rests with the DOCC. However, the spe-cially designated TCF's assist in carrying out the mis-

exercises technical supervision over specified DCSwideband facilities. The FCO is selected on its accessi-bility to the systems and stations under its control andorderwire capabilities to each Intermediate ControlOffice and to other TCF's within the designated areaof responsibility. When a TCF is designated as a FCOit will have technical supervision over all links underits control. All TCFs and PTF’s along the route, aswell as all connected TCF's and PTF’s. These stationswill respond to the FCO’s technical direction. TCF per-sonnel assume the following added responsibilitieswhen the TCF is designated as a Facility Control Of-fice:

(1) n operational status of assigned facili-ties.

(2) Direct remedial action to correct service degra-dations which affect system performance and userservice.

(3) Direct restoral and reroute action.(4) Direct special testing to isolate system and cir-

to determine capability of the system toor uniqueservice requirements.adjacent TCF’s and PTF’s whenever a

that may have an effect on the opera-

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ters within established standards.(7) Establish procedures for subordinate stations

to forward to the FCO test and alignment data;analyze that data looking for trends toward adversesystem performance; forward performance data to theDOCC and operation and maintenance activities.

(8) Implement transmission facility activation,deactivation, and configuration change schedules.Notify appropriate elements when implementation iscompleted or delayed.

(9) Maintain appropriate logs and system perfor-mance records.

(10) Report assigned facility operation status tohigher levels of authority and respond to their direc-tion.

b. Circuit Control Office. One TCF through which acircuit passes is designated in the technical service or-der as the CCO. CCO personnel are responsible for thefollowing actions:

(1) Activation of the circuit from end-to-end andensure that the service order is completed 72 hours be-fore the scheduled service date.

(2) Direct overall lineup and subsequent testingto ensure that the circuit meets the parameters estab-lished for the grade of service.

(3) Advise the appropriate elements of any circuitrestrictions which might effect service.

(4) Prepare and implement out-of-service qualitycontrol test schedules.

(5) Record and maintain on file the required testsummary.

(6) Initiate isolation and correction of any troublediscovered as a result of quality control testing.

(7) Coordinate end-to-end testing whenever thecircuit routing is substantially changed or it has beenrestored after a prolonged outage.

(8) Make certain that all patches and cross-con-nects are removed when the circuit is discontinued.

(9) Report to high level of authority, uncoopera-tive action on the part of any TCF, PTF, or commercialagency during circuit activation or deactivation.

(10) Coordinate restoration of assigned circuits in-cluding coordination of reroute action.

(11) Direct and coordinate troubleshooting to iso-late and clear the trouble which is disrupting service.

(12) Restore the circuit to its normal path as soonas possible. This is done through constant review oftemporary path changes.

(13) Keep all elements advised as to progress ofrestoration work.

(14) Establish procedures for handling and record-ing service interruptions and bring any conditions be-yond the capability of the TCF’s, PTF's and/or CCO tothe attention of the appropriate element.

d. Intermediate Control office. If the circuit layoutis such that the FCO or the CCO is not in the best posi

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tion to test and coordinate activities of intermediateTCF's, another TCF can be designated as an Intermedi-ate Control Office. The ICO will be designated on theservice order at the time of layout and TCF personnelhave the general responsibility of the assigned seg-ment as well as the following:

(1) Conduct in-service testing and take correctiveaction in the case of signal degradation, includingthose signals not alarmed by pilot frequencies.

(2) Activate, deactivate, and change the circuit in

accordance with TSO's.(3) Initiate chit

Section II. SYSTEM SERVICE INTERFACES AND TYPES OF SERVICE

2 - 7 . I n t r o d u c t i o n

In this section and the typesof service will technical con-troller to make the most efficient use of circuits andsystems available, an understanding of the overallDCS and the facilities serviced is necessary. In addi-tion to understanding the make-up of the DCS, thetechnical controller should be familiar with the trans-mission media used; communications facilities in-volved; the facilities which use the DCS mainlinetrunk routes as a transmission path; and the types ofsignals which are generated by these facilities. The in-formation covered in this Election is listed below to-gether with appropriate paragraph references:

a. DCS common user network (para 2-8).b. Transmission media (para 2-9).c. Communications facilities (para 2-10).d. Relay Centers (para 2-11).e. Automatic Voice Network (AUTOVON) (para

2-12).f. Automatic Digital Network (AUTODIN) (para

2-13).g. Types of signals (para 2-14).

2-8 . DCS Common User Ne twork

a A common user network is one that provides a setnumber of channels of voice or data communicationsfor use by an even larger number of users on a sharedbasis. A user of a communications network can be aperson making a telephone call; a communications cen-ter originating or receiving many teletype messages,data or facsimile signals; or a solitary teletypewritermaintaining contact with another like machine. Theoriginating user am be linked to another activity with-in the same geographical area or in another geographi-cal area. The point to remember is that the availablechannels of communications are shared by all or theyare for "common usage”. Within the DCS the majorityof the available channels are for common usage. Dedi-cated circuits, which make up the remaining channels,are established to support the traffic originating atdedicated facilities which provide communications ofcommon interest, high volume, or priority traffic cus-

2-9 . Transmiss ion L inks and Media

(1) High Frequency Radio. This media can cover

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Figure 2-1. Example of a world-wide common user network.

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distances up to 6,000 miles. The ground distance be-tween stations is dependent upon the equipment se-lected and station design. A limitation on high fre-quency radio is the small number of multiplexed chan-nels which can be carried, usually 4 voice frequency

(2) Line of sight Radio. These radio links operatein the very high frequency, ultra high frequency or mi-crowave frequency regions. There must be 8 line ofsight path between the transmitting and receiving sta-tions, however, this limitation is overshadowed by thecapability of such links carrying a high density of mul-tiplexed communications channels.

(3) Tropospheric Scatter Radio. This type ofmedia relies on the forward scatter technique or propa-gation. Tropospheric scatter can cover distances be-tween 100 to 500 miles and carry a large number ofmultiplexed channels, depending upon system design.This media of transmission is also referred to as over-the-horizon propagation and does not require a line-of-eight path between stations.

(4) Satellite Radio. The distances covered by thismedia depends upon how high above the earth thesatellite relay station is positioned. The distance be-tween earth stations usually vary between 2,000and 6,000 miles. The transmission link is capable ofcarrying many multiplexed channels. The main limita-tion is that the channel capacity and position of thesatellite relay station cannot be upgraded or changed.

(5) Metallic Links. Metallic links can be coaxialcable, paired cable, or open wire. A metallic link can beof all one type or by use of interfacing equipment be amixture of two or all three of the types. A metalliccable link can be either submarine or landline. Metallicsystems can carry a low density or a high density ofmultiplexed channels depending on the equipment andthe type of cable selected and user requirements. Themajor limitation is in the construction of such systems.Right-of-way must be arranged and cable or wire laidto make the physical connection between the twobreakout points. An added factor is the maintenance,and when needed, the repair of the outside plant facili-ties.

b. Transmission links utilizing line of sight paths,tropospheric scatter, and metallic media can cover therequired distance between breakout points directly ormay require intermediate stations to span the distancebetween the two stations providing the breakout capa-bility. These intermediate facilities are called relaystations for radio systems and repeater stations formetallic systems. In either case the relay or repeaterstation performs the same function It will equalizeand simplify the incoming signals to permit the re-transmission of a signal that, as near as possible, dupli-cates the original transmitted signal.

c. Referring to figure 2-1, the common user net-

work depicted can be made up of all the types of trammission media described above. In addition, any one orall of the transmission links shown could have one ormom intermediate relay or repeater stations as part ofthe link, or span the distance without the need of thesestations. The type of equipment selected and the makeup of the transmission link is determined by the dis-tance between breakout points, strategic and economicfactors, and the technical parameters required to pro-vide the appropriate type and grade of service to theusers.

2 - 1 0 . C o m m u n i c a t i o n s F a c i l i t i e s(fig. 2-2)

The communications facilities, which when connectedtogether to form the worldwide common user systemcan be classified as tributary stations, major relay sta-tions, or minor relay stations.

a. Tributary Stations. A tributary station providescommunications services, telephone, teletype, dataetc., to activities located at the same base or installa-tion. It is not a requirement that tributary stations belocated on a base or installation. It could be positionedin a civilian community where there is a concentrationof DCS users. The equipment installed at the tributarystation is compatible to that of the relay station ormessage switching center that provides access to theDCS. In figure 2-2, the facilities located at Camp Pand Camp J, are tributary stations located on the installation. From the tributary station, lines extendoutward to the user equipment. This equipment can bea single teletypewriter; banks of teletypewriters lo-cated in the installation communications center; dataterminals; a computer; a facsimile machine; and the in-stallation telephone exchange. The telephone ex-change further extends the service of the tributary sta-tion to each authorized telephone user on the instal-lation. Stations PDQ and LMN are tributary stationsnot located on an installation, but in a town or city inwhich there are a number of authorized usersrequiring access to the DCS. The transmission link be-tween the tributary station and its associated accessstation to the DCS can be direct or require the use ofrepeater or a relay station.

b. Major and Minor Relay Station Tributary sta-tion access to the DCS is through a relay station,Traffic flows through the access relay station onto thesystem to the distant tributary station. Relay stationsare classified as major or minor depending upon their`position in the DCS.

(1) Major Relay Station. In figure 2-2, DCSStation ABC can be classified as a major relay station.It is situated at a nodal (or junction) point of two ormore DCS subsystems. In addition to passing trafficoriginating at or destined for a connected tributarystation, it also acts as a circuit switching station. The

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Figure 2-2. Interconnection of communications facilities, simplified diagram.

2-7

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station is located at the junction of Government ownedSystems #1, #2, and #3 of the world-wide network, andis also an access point to leased circuits carried over acommercial facility, and a Government owned satellitesystem. Signals entering ABC on System #3, as anexample, from tributary station LMN or beyond DCSStation XYZ, and not destined for a connected tribu-tary station, would be switched to leave the nodalpoint on Government System #1 or #2, the commercialfacility, or the Government satellite system. Theswitching can be accomplished on a channel, group orsupergroup level. DCS Station ABC provides manyrouting capabilities for signals originating at an associ-ated tributary station, including interconnection ofusers located at any of the serviced tributary stations.

(2) Minor Relay Station. DCS Station XYZ (fig.2-2) can be classified as a minor relay station. Theamount of installed equipment would be much lessthan that of DCS Station ABC since it is not at a nodalpoint. It services only one tributary station, and pro-vides access only to the East or West on System #3.

2-11. M e s s a g e R e l a y C e n t e r I n t e r f a c e(fig. 2-3)

It is not feasible (economically or practically) to haveeach teletypewriter user connected directly to everyother users machine. Economic interconnection is es-tablished through a complex subsystem network ofmessage relay centers. The worldwide DCS is used asthe vehicle to transmit messages from one user to an-other. Individual teletypewriter signals are multi-plexed into composite signals which are then trans-mitted over the DCS system voice channels. So thatevery teletypewriter user can transmit to any otheruser, a system of message relay centers has been estab-lished to switch (or relay) the messages from one sys-tem to another and move it from the originator to theaddressee as quickly as possible. The message relaycenter may be an activity serviced by a tributary sta-tion or a tributary station itself. Message relay centersare classified into three categories: manual, semiauto-matic, and automatic.

a Manual and Semiautomatic Message Relay Cen-ters. The manual and semiautomatic message relaycenters employ the torn tape method of operation. Anoperator tears the incoming message tape off of a re-ceiving machine, reads the routing indicator, and handcarries it to the transmitting position. This is a rela-tively slow method since the speed of passing a

ge tape through the office is dependent upon theand accuracy of the operator in reading the rout+

ing indicator, carrying it to the transmitting position,and preparing it for retransmission. The semiauto-matic message relay center speeds up the retransmis-sion process by having an automatic numbering proc-ess and tandem transmitter distributors with auto-

matic switching between them.b. Automatic Message Relay Centers. There is no

need for operator intervention during normal op-eration of this type of message relay center. Messagesam automatically passed, via cross office equipmentfrom the receiving machine to the transmitting posi-tion, renumbered and retransmitted to the next relaycenter or to the addressee. This permits rapid relay ofmessages through the relay center. Delay is only de-pendent upon the speed at which the cross-officeequipment operates. So that this facility can operate atmaximum speed and efficiency, there is a need tomaintain precise accuracy in the production of theoriginal message tape, and high quality of the DCS cir-cuits over which the message travels.

2-12. AUTOVON INTERFACE(fig. 2-3)

a. The worldwide DCS main-line trunk routes pmvide the transmission path for voice frequency com-munications over the Automatic Voice Network(AUTOVON) another DCS subsystem. The basicobjective of AUTOVON is to establish a common-userautomatic switching network that provides worldwidecompatibility, reliability, flexibility, and greater sur-vivability of telephone communications. The voicecommunications capability is provided between De-partment of Defense users and between Department ofDefense users and certain non-DoD users. The systemis established primarily for voice communications, butit is capable of handling graphic and data transmis-sions on a user-to-user basis. It is capable of handlingsecure communications when the appropriate equip-ment is installed at user locations. For operational andcontrol purposes, the AUTOVON switch has a built-inTCF which functions as a tributary station to a DCSmajor or minor relay station.

b. The Automatic Voice Network is intended tooffer identical services worldwide to its users. Servicesthat are available to users system wide are as follows:

(1) Normal Service. It provides the capability fordirect dialing from one user to another on a worldwidebasis. In instances where limited trunking facilitiesare available, the user will place the call through alocal operator or a Dial Service Assistant.

(2) Four-Wire Service. Selected subscribers toAUTOVON are provided with a special I-wire tele-phone for direct access to the network. Datasubscribers are provided access to specially condition-ed AUTOVON data circuits. The signalling from a 4-wire instrument is dual-tone, multifrequency. Thefour-wire service subscribers can also be provided withup to three levels of precedence for pre-emption oflower level precedence calls when necessary.

(3) Off-Hook Service. The off-hook service subscriber is immediately connected through the network

2 - 8

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Figure 2-3. Subsystem interface with the DCS.

to a predesignated subscriber as soon as the handset islifted from the cradle.

(4) Special Networks. These special networks mayallow complete privacy to specially designated users orallow them access to the entire AUTOVON network.These special networks fall into two categories:

(b) Category 2 provides special treatment tousers within a special interest community. This com-munity of special interest can be within one geographi-cal area or worldwide. General purpose subscribers canbe prevented from calling into category 2 networksand category 2 subscribers can be denied access to thegeneral purpose network.

c. Normally connection through the AUTOVONfrom user to user will be completed in about 4 seconds.Difficult connections may take up to 10 secondsthrough unusual or complex routing. This is switchingtime only and excludes the time required to dial. Off-hook service connections are normally established inless than 2 seconds. So that designed speed and qualityof service can be realized, AUTOVON designated DCScircuits must be maintained at a high quality.

2-13. AUTODIN Interface(fig. 2-3 and 2-4)

a Another communications subsystem interfacewhich a technical controller must be aware of and

familiar with is the Automatic Digital Ne(AUTODIN). AUTODIN interstation trunks are supplied by the worldwide DCS main-line trunk routes.The transmission quality on the AUTODIN trunks isthe responsibility of the DCS Station Technical Con-trol Facility. The technical control personnel monitorall incoming dc circuits and breakdown voicefrequency telegraph carrier into individual dc circuits.These circuits are then extended to the AUTODINswitch. Like the AUTOVON, the AUTODIN SwitchingCenter has a built-in Technical Control Facility for op-erational and control purposes.

b. AUTODIN Is a store and forward switchingnetwork for the transmission of digital data. TheAUTODIN is a high speed, flexible, computer con-trolled network which provides the Department of De-fense and other Government agencies with digitalcommunications. The flexibility of AUTODIN isillustrated by the following capabilities:

(1) Processes traffic on a store and forward basisbetween two widely separated users.

(2) Sends and receives traffic to and from users attransmission rates between 75 and 2400 baud and be-tween AUTODIN switching centers at rates up tobaud.

(3) Accepts traffic from teletypewriter, punchedcard terminals, magnetic tape terminals, and com-puters.

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Figure 2-4. AUTODIN interface with the DCS.

2-10

(4) Exchanges traffic between users whose equipment operates at different speeds and use differentcodes and formats.

c. The AUTODIN interface with a DCS Station isillustrated in figure 2-4. AUTODIN tributary stationsare connected to the AUTODIN Switching Center(ASC) directly or via AUTODIN conditioned trunks ofthe Automatic Voice Network (AUTOVON). The ASCis connected for transmission to another ASC via theDCS Station which acts as the gateway to the DCS.The traffic is cleared through the station and routedout on predetermined and preconditioned circuits overcable, radio, or satellite systems. These circuits can beover Government owned facilities or over leased facil-ities.

d. The AUTODIN Switching Center can be con-nected to another ASC over the AUTOVON as aprimary route or, in the event of a failure of a primaryroute, as a backup circuit through the establishment ofon-call patches. In addition, users of AUTODIN whodo not require full time access to the ASC can be con-nected to the switching center over AUTOVON on acall-up basis. In cases where AUTODIN is routed overAUTOVON for restoral or for non-full period users ofthe AUTODIN to gain access to the ASC, it is theresponsibility of the technical controller at the ASC toestablish the path. The controller dials up the distantASC or user, establishes voice contact, makes the re-quired equipment connections to the circuit, and thenturns the circuit over for digital communications. Af-ter restoral of normal routing or at the end of the userreal-time schedule, the originating technical controllercoordinates the release of the called-up circuit.

2-14. Types of Signals

A technical controller can expect to find signals fromany type of terminal equipment passing through theTCF. The signals from these equipments include butare not limited to dc teletype loops, speech, data,facsimile and voice frequency carrier telegraph(VFCT). The signals may be broken down to a channellevel or pass through the Technical Control Facility atthe group or supergroup level. The terminal equipment generating the data, facsimile and VFCT signals,produce a composite tone in the voice frequency rangeand the tones are then normally transmitted over a

TM 11-5895-1012-10

voice frequency channel that has a range from300-2800 Hertz (Hz) (2500 Hz bandwidth, (nominal 3kHz channel)) or 300-3400 Hz (3106 Hz bandwidth(nominal 4 kHz channel)). There are some instances,such as with television or other wideband signals,where the composite tones require a wider bandwidth.In these cases two or more adjacent channels arespecially prepared for transmission of the widebandsignal.

a. The voice frequency speech signals can originatefrom 2-wire or 4-wire instruments with almost anytype of signaling, The power for this circuit is gen-erated as the user speaks into the telephone and thefrequency complexity of the signal is that of ordinaryspeech.

b. DC teletype signals originate at the teletypemachine and consists of a series of coded pulses, (eachone unique to a keyboard character) where a direct cur-rent is either flowing or not flowing. The teletypesignal can be passed through the station as dc toanother teletypewriter, but most usually it is inputedto voice frequency carrier telegraph equipment wherethe pulses generate tone signals for one channel of theVFCT composite output tone.

c. Voice frequency carrier telegraph systems acceptfrom 2 to 16 or more teletypewriter signals and multi-plexes the tones generated by each teletype signal intoa composite “tone package”. Each teletypewriter signaloccupies a different portion of the frequency spectrumof the tone package, which is then transmitted over asingle voice frequency channel.

d. Data and facsimile terminal equipment functionsin the same manner as a VFCT terminal. In convertsthe intelligence from mechanical linkage or lightintensity into a unique data stream or series of toneswhich can then be transmitted over a single voice fre-quency channel. Data signals can originate at a singledata terminal or from an AUTODIN Switching Center.

e. At the Technical Control Facility the controllermonitors and tests these signals at the voice frequencylevel, except in those instances where a dc teletypeloop appears at a dc patch panel. Various types of testequipment, which will be discussed later, are availablefor the technical controller to check the quality andlevel of the signals passing through the station.

Section III. THE TECHNICAL CONTROL FACILITY

2-15. General

a. The Technical Control Facility (fig. 2-5) is thatelement of a communications network that providesthe technical control, interfaces transmission elementsof the DCS, and interfaces the user with the System.The management of the communications paths is doneat the TCF and subordinate Batch and Test Facilities.

As noted in the previous section, the communicationspaths can be over any of the following transmissionmedia singly or in serial combinations:

(1) Submarine cable.(2) Land-line cable or wire circuits.(3) High frequency radio circuits.(4) Tropospheric scatter radio circuits.

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(5) Line-of-sight radio circuits.(6) Earth satellite radio circuits.

b. The Technical Control Facility functions to pro-vide technical direction, coordination, technical super-vision of transmission media and equipment, qualitycontrol, communications restoral and status reporting.These functions are accomplished with the followingfive basic operations:

(1) Patching (r&oral, test, monitor).(2) Coordination (to far-end, to user, to mainte-

name).(3) Testing (insertion of a known signal with

measurement for frequency, level, distortion, etc. onan out-of-service basis).

(4) Monitoring (measurement of existing circuitconditions or traffic, without insertion of a test signal,on an in-service basis).

(5) Reporting (circuit and system status to users,adjacent TCF’s, circuit distant end, operation andmaintenance activities, etc., as well as all required re-petitive reports).

c. Normally, the TCF is collocated with a tape relayand switching center, and/or a carrier terminal facil-ity, but it may be located with either a radio station ortelephone facility. The choice of location is usuallybased on a study of all factors involved in site selec-tion. By choosing to collocate the Technical ControlFacility with the tape relay or switching facility elimi-nates the necessity of providing additional intrasta-tion links. All circuits, regardless of the media usedand type of signal, are available at jack appearances atthe TCF. These appearances provide the flexibility re-quired by a TCF. There are exceptions to this rulewhere circuits transit the station on a through grouplevel. However, there are group access points, whichallows access to the circuits being carried on a throughgroup for testing purposes. These access points nor-mally located at the multiplex equipment outside theTCF, can also be used as patching points for restoral orrerouting of groups in the event of system failure.

2-16. Technical Control ConfigurationBlock Diagram

(fig. 2-6 and 2-7)

a. General. The block diagram illustrates the inter-relationship among the major equipment of the Tech-nical Control Facility together with the terminalequipment. Although the Technical Control Facility ofmany DCS Stations may not require access to all trans-mission modes shown in figure 2-6, the TCF configu-ration should be essentially the same, whether the sta-tion is located at a transmission nodal point or termi-nal point. The block diagram includes all major equipment and patch facilities which are involved in theoverall technical control function, however, all itemswill not necessarily be located with the immediate TCF

2-12

operating space, as indicated on the diagram. Figure2-7 shows a typical floor plan for a Technical ControlFacility.

b. Primary Patch Bay.(1) Dc and Digital. The dc and digital primary

patch bays are those areas within the TCF where dcand digital user circuits can be patched, monitored andtested. Signals may be high or low level and baud ratedepending on the user terminal equipment.

(2) Voice Frequency (VF). The vf primary patchbay is that area within the TCF where voice frequencycircuits can be patched, monitored and tested. Signalwill have varying levels and signalling schemes de-pending on the user terminal equipment.

c. Circuit Conditioning Equipment. Circuit condi-tioning equipment, such as amplifiers, pads, hybridsetc., signalling equipment, digital line interface units(DLIU), and circuit ancillary equipment is so installedand wired into the TCF so that it will appear betweenthe primary and equal level patch bays.

d. Equal Level Patch Bay. The equal level patch bayis that area within the Technical Control Facilitywhere voice frequency channels at the standard TestLevel Point (TLP (OdBr send and receive)) utilizingstandard in band signalling can be patched, monitoredand tested.

e. Group Patch Bay. The group patch bay is thatarea where multiplexed groups (usually 12 channelscan be patched, monitored, and tested.

f. Coaxial Patch Buy. The coaxial patch bay is thata associated with the TCF where signals requiring

distribution via coaxial cable can be patched, moni-tored, and tested. Signals which require coaxial cabledistribution include supergroup, baseband, high speedTime Division Multiplexed signals, etc.

g. Dc Circuit Bay (Low/Level) and Digital PatchBuy. The dc circuit and digital patch bays are thoseareas within the Technical Control Facility where lowlevel analog or digital data circuits can be patchedmonitored and tested

h. Patch Panel Appearances. Patch panel appearances are furnished and installed for the following

(1) Allow for substitution for those units whichare out of service because of test and maintenance ofthe facility.

(2) Allow for substitution of equipment strings(circuit or wideband segments) as they occur betweenthe primary and equal level patch panel appearances.

i. Time Division Multiplexer Equipment (TDM). Thetime division multiplexer equipment is a technique toaccept various digital signals (both data and teletype)with different bit rates and combine them into a singlehigh bit rate stream for transmission. The demulti-plexer section reconstructs the signals at the samenominal rate at which they entered the multiplexerThis equipment can be used in tandem to accommo-

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Figure 2-5 Technical Control Facility, interface diagram.

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Figure 2-6. Technical Control Facility, configuration block diagram.

2 - 1 4

date a wide range of data rates to produce a singleserial stream of information, with its associated tim-ing.

j. Pulse Code Modulation Equipment (PCM). Thepulse axle modulation equipment normally accepts theanalog signal (the modulating signal) and samples it ata predetermined rate. The sample is then quantizedand coded so that each element of information consistsof differing numbers of pulses (marks and spaces).This equipment generally uses an eight bit samplerate.

k. Modems.(1) Digital Modems (VF). This is a modem which is

used to convert direct current signals appearing on thedigital patch bay to the analog form for appearance onthe equal level patch bay. This equipment requires anominal bandwidth of 4 kHz

(2) Special Digital Modems (Group). Input to thismodem is in digital form from the digital patch bay.Its output is analog form and appears on the grouppatch bay in the standard frequency division multi-plexed group frequency bandwidth of 60 to 108 kHz.

(3) Special Modem (Supergroup). Input to this mo-dem is in digital form from the wideband user/switchor TDM. Its output in analog form appears on the su-pergroup portion of the coaxial patch bay in the stand-ard FDM supergroup frequency bandwidth of 312 to552 kHz.

2 -17 . Voice F requency Ci rcu i t s

a. General. All voice frequency (vf) users includingAUTOVON, AUTODIN, and AUTOSEVOCOMswitches, communications centers, PABX's, localswitchboards and tactical multiplex equipment accessthe TCF by way of the Primary Patch Bay. Four-wirefixed station multiplex equipment utilizing 2600Hertz signaling access the TCF by way of the EqualLevel Patch Bay. All conditioning and signallingequipment required to achieve compatibility betweenusers and the transmission media is electrically con-nected between the Equal Level Patch Bay and the Pri-mary Patch Bay. The Primary Patch Bay terminates 2,4, 6, or 8 wire user circuits. The Equal Level Patch Bayserves at the principal point of interface and restora-tion in the Technical Control Facility. Circuits appear-ing at the Equal Level Patch Bay appear as 4-wire bal-anced pair circuits (AUTOVON switch circuits havingPilot Make Busy capability appear as five-wire cir-cuits). The Equal Level Patch Bay is the zero (0) testlevel point in the station, that is, OdBr send and re-ceive. DCS standard supervisory signals appear as2600 Hertz tones at the Equal Level Patch Bay.

b. Circuit Descriptions. The following is a list of thevarious types of voice frequency circuits which may becommonly found appearing in the Technical ControlFacility. A TCF may service other circuits which are

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not included in the following list. A description of eachcircuit follows in the paragraph indicated.

(1) Two-wire voice user with 20 Hertz signalling(para c below).

(2) Two-wire voice user with loop signalling (parad below).

(3) Two-wire voice user with E&M signalling (parae below).

(4) Two-wire voice user with standard integral sig-nalling (para f below).

(6) Four-wire user with standard integral signal-ling (para g below).

(6)below).

Four-wire user with 20 Hertz signalling (para h

(7) Four-wire user with loop signalling (para i be-low).

(8) Four-wire data user cable to TCF (para j be-low).

(9) Two-wire or four-wire voice user using non-standard in-band signalling (nonstandard signallingunit at user terminal) (para k below).

(10) Four-wire user with DX signalling (para l be-low).

(11) Four-wire PBX trunk to AUTOVON (PBXcable to TCF) (para m below).

(12) Four-wire data user with DX signalling (paran below).

(13) Two-wire PBX cable access line (two to fourwire conversion at PBX) to local AUTOVON switch(para o below).

(14) Four-wire AUTOVON subscriber telephonecable to TCF (loop resistance less than 700 ohms) (parap below).

(15) Four-wire AUTOVON circuit (remote two-wire PBX subscribers) (para q below).

(16) Four-wire AUTOVON special grade circuits(AUTOVON subscribers (data) and inter-switchtrunks) (para r below).

(17) Four-wire AUTOVON voice grade circuits(para s below).

(18) Voice and telegraph users connected to HighFrequency radio transmission media (pars t below).

(19) Four-wire voice frequency carrier telegraph(para u below).

(20) Fixed station multiplex interconnection (parav below).

(21) Non-DCS multiplexer user to DCS user onbase, or using DCS transmission media (para w below).

(22) Four-wire entrance toll cable (para x below).(23) Four-wire connections to High Frequency ra-

dio systems (para y below).c. Two- Wire Voice User With 20 Hertz Signalling

(fig. 2-8 ). The users for this circuit are either atwo-wire switchboard or an individual two-wire userusing 20 Hertz ringing source. This circuit providesecho suppression and control in order to minimize

2-15

TM 11-5895-1012-10

Figure 2-7. Technical Control Facility, typical floor plan.

2 - 1 6

TM 11-5895-1012-10

Figure 2-81. Typical voice frequency circuits (sheet 1 of 5).

2-17

TM 11-5895-1012-10

Figure 2-82. Typical Voice Frequency Circuits (sheet 2 of 5)

2-18

echoes arising from four-wire to two-wire conversions.The circuit makes an appearance at the Primary PatchBay by way of outside plant cables. Between the Pri-mary and Equal Level Bays, conditioning is providedby pads, amplifiers, and two-wire/four-wire terminat-ing sets. Signalling conversion is provided by E&M/20Hertz converters and 2600 Hertz signalling unit. Thisconfiguration can apply to “hotline” or dedicated cir-cuits, orderwires, and switchboard trunk circuits.

d. Two-Wire Voice User With Loop Signalling (fig.2-8 ). The users for this circuit a either two-wireswitchboards or two-wire individual users which useloop signalling. The circuit is the same as that in cabove with the exception of using E&M/dial loop sig-nalling converters instead of E&M/20 Hertz converters.

e. Two-Wire Voice User with E&M Signalling (fig.2-8 ). The user for this circuit is either a two-wiremitchboard or individual user with E&M signalling. Itis noted in this circuit that a separate cable is usedin the on-base cable to carry the E&M (dc) lea& fromthe user location through the Primary Patch Bay tothe SF 2600 unit. Conditioning items are twowire/four-wire terminating set, repeat coil, echo suppressor, and pads and amplifiers for level adjustment.These configurations have applications as user to cen-tral officer inter-connections and user-to-user link.

f. Two-wire Voice User with Standard Integral Sig-nalling (fig. 2-8 ). The user of this circuit is a two=wire w who has 2600 Hertz inband signal incorpo-rated into the terminal telephone equipment. A twowire/four-wire terminating set performs the necessaryhybrid functions, and pads and amplifiers are installedfor level adjustment. This circuit is for special applica-tion to users with this requirement and may have anecho suppressor added if so specified.

g. Four-Wire VF User with Integral Signalling (fig.2-8 ). This user provides his own 2600 Hertz in-band signalling at the user station or the circuit maybe a data circuit. In any cam, no signalling conversionis required at the Technical Control Facility. Betweenthe Primary and Equal Level Bay appearances, repeatcoils, pads, and amplifiers are supplied for conditioningand level adjustment Amplitude equalizers may be re-quired depending on the service.

h. Four-Wire VF User with 20 Hertz Signalling (fig.2-8 ). The users for this circuit are either a four-wire switchboard or an individual four-wire user whichuses 20 Hertz signalling. A four-wire physical circuit isused for the on-base cabling. Conditioning between thePrimary and Equal Level Bays consists of pads andamplifiers for level adjustment. E&M/20 Hertz con-verters and SF 2600 units are required for telephonesignalling conversions. This configuration can be ap-plied to dedicated lines, and orderwire circuits.

i. Four-Wire VF User with Loop Signalling (fig.

TM 11-5895-1012-10

2-8 ). The users of this circuit can be either a four-wire switchboard or individual user which uses loopsignalling. The circuit flow is the same as in h aboveexcept that an E&M/DC loop converter is used insteadof an E&M/20 Hertz converter.

j. Four-Wire Data User Cable to TCF Without Sig-nalling (fig. 2-8 This circuit is for high speeddata users, AUTODIN interswitch trunks, and datalines for secure voice circuits. In addition to level ad-justment, amplitude or delay equalization units maybe required in the strings of conditioning equipment.

k. Two-Wire or Four-Wire Voice User Using Non-Standard Inband Signalling (fig. 2-8 ). After enter-ing the TCF by way of the Primary Patch Bay, thenon-standard inband signalling is converted to stand-ard inband signalling before it appears at the EqualLevel Bay. This is accomplished by using a signallingunit compatible to the non-standard inband signal be-ing received, converting it to E&M signalling, and ap-plying the E&M pulses to the SF 2600 unit through apulse link repeater.

l. Four- Wire PBX or User with DX Signalling (fig.2-8 ). The users for this circuit are either auAUTOVON PBX access line or an AUTOVON four-wire user. DX-1 signal units and repeat coils are usedat the user locations either to conserve cable pairs orwhere loop resistance exceeds 50 ohms. If the AUTO-VON switch is off base, the circuit proceeds to theEqual Level Bay with the necessary conditioning andtelephone signal conversion units located between thePrimary and Equal Level Patch Bay appearances. Ifthe AUTOVON switch is collocated on-base, the cir-cuits do not access the Equal Level Patch Bay, butafter passing the Primary Patch Bay, the circuits areconditioned for proper levels and E&M signalling, andmake another appearance at the Primary Patch Bayand connect to the AUTOVON switch.

m. Four- Wire PBX or User with E&M Signallingto AUTOVON (PBX Cable to TCF) (fig. 2-8 ). Thisuser circuit is similar to the circuit described in l aboveexcept there is no requirement for DX-1 signal unitsat the user or the TCF. This is because the user andTCF are closely located and plant cable pairs with lessthan 50 ohms loop resistance can be used.

n. Four-Wire Data User With DX Signalling (fig.2-8 ). This circuit is similar to makeup to that dis-cussed in l above, with necessary amplitude or delayequalization devices. The circuit is of high speed dataquality but can be called up by way of the AUTOVONswitch when required.

o. Two-Wire PBX Cable Access Line to LocalAUTOVON Switch (Two to Four-Wire Conversion atthe PBX) (fig. 2-8 ). This circuit involves connec-tion of a two-wire on-base telephone switchboard to anAUTOVON switch which is also located on the samebase. This PBX (access circuit appears only on the Pri-

2-19

TM 11-5895-1012-10

Figure 2-83. Typical Voice Frequency Circuits (sheet 3 of 5)

2 -20

TM 11-5895-1012-10

Figure 2-84. Typical Voice Frequency Circuits (sheet 4 of 5)

2-21

TM 11-5895-1012-10

mary Patch Bay and does not access the Equal LevelPatch Bay as the circuit involved does not go off base.A two-wire/four-wire terminating set shall be requiredat the PBX location. Normally the E&M leads will beextended as shown in figure 2-8 and described in eabove. Where the loop resistance exceeds 50 OHMS, sig-nal extension units (DX) shall be required at the PBXlocation and at the Technical Control Facility. Splitcontrolled echo suppressors, pads and amplifiers whenrequired are inserted into the circuit as shown.

p. Four-Wire AUTOVON Subscriber Telephone Ca-ble to TCF (Loop Resistance Less Than 700 Ohms) (fig.2-8 ). This AUTOVON telephone is located lessthan 700 ohms from the collocated TCF and AUTO-VON switch. In this case the circuit accesses the Pri-mary Patch Bay, connects to repeat coils and level ad-justment equipment, and returns to the Primary PatchBay with E&M lead appearance and then proceeds tothe collocated AUTOVON switch.

q. Four-Wire AUTOVON Circuit (Remoter Two-Wire PBX Subscribers) (Fig. 2-8 . This trunk cir-cuit originates at the AUTOVON switch collocatedwith the Technical Control Facility. The circuit inter-connects at the Equal Level Patch Bay to transmissionmedia for service to remote two-wire PBX AUTOVONsubscribers. provision is made for an echo suppressorwhen the PBX is two-wire. This circuit appears on theEqual Level Patch Bay and pads and amplifiers areprovided for level adjustment. As this circuit is desig-nated to interconnect with multiplex facilities, a pilot-make-busy (PMB) circuit is used as follows:

(1) The Group Pilot Control (GPC) alarm circuitfurnishes output leads (one for each channel in the as-sociated group) which are grounded when group fail-ure occurs. The GPC alarm indicates normal operationwith an "open" circuit condition.

(2) On each channel associated with group usingthe GPC alarm function, the GPC alarm leads are ex-tended to the sleeve conductor of the associated EqualLevel Patch Bay channel line jack.

(3) On each AUTOVON trunk circuit the inputto the sleeve con-

on the Equal LevelPatch Bay equipment jack. The coil of the PMB relayhas sufficient voltage connected to it to operate the re-lay when ground is applied to the GPC output lead.

(4) The PMB relay operates as follows:(a) Open the E lead connection from the SF unit

y after the alarm condition50 seconds depending upon

conductor to the Pri-

(AUTOVON Subscribers (Data) and Inter-SwitchTrunks) (Fig. 2-8 ). This circuit operates the sameas that described in q above except that delay equaliza-tion devices are provided for data use.

s. Four-Wire AUTOVON Voice Grade Circuit (Re-mote AUTOVON Four-Wire User) (fig. 2-8 ). Thiscircuit operates the same as that described in q aboveexcept that the circuit connects to remote AUTOVONfour-wire users.

t. Voice and Telegraph Users Connected to HighFrequency Radio Transmission Media (fig. 2-8 Voice and telegraph using high frequency radio trans-mission for long distance communications accesses thePrimary Patch Bay of the Technical Control Facility asaudio or dc circuits. The circuits shown illustrate thesetup for high frequency independent sideband trans-mission made up of four 3-kHz bandwidth channels.The typical four channel system depicted is equippedfor three voice channels (A2, B1, B2) and one VF tonepackage consisting of 16 date channels (Al). Line con-ditioning equipment for these circuits before they ac-cess the Equal Level Patch Bay includes: a telephoneterminal set or channel for each of the three voice cir-cuits and regenerative repeaters and/or isolation relaysfor the dc circuits. Separate pads and/or amplifiers areprovided for the VF tone package before it accesses theEqual Level Patch Bay.

u. Four-Wire Voice Frequency Carrier Telegraph(VFCT) Packages (fig. 2-8 ). This circuit consists ofmultiple teletypewriter signals which enter the Tech-nical Control Facility at the Primary and Dc PatchBays and are then combined into a "tone package” at avoice frequency carrier telegraph (VFCT). The VF tonepackage employs a nominal 4-kHz channel bandwidthand appears at the Equal Level Patch Bay as an audiosignal. Although VF level control can, in most cases,be achieved by the VFCT equipment, pads and ampli-fier may be installed in the circuit prior to accessingthe Equal Level Patch Bay, if necessary.

v. Fixed Station Voice Frequency Multiplex Inter-connection (fig. 2-8 ). This is the normal configura-tion of a frequency circuit between the EqualLevel Patch Bay and the fixed station multiplex equipment. The only interface requirements are level con-trol and the PMB circuit which is described in q above.

w. Non-DCS Multiplex Users to DCS User On-Baseor Using DCS Transmission Media (fig. 2-8 ). Thiscircuit is provided to interface a tactical multiplex us-ing a non-standard method of telephone signalling touser circuits conditioned for the standard signallinginterface at the Equal Level Patch Bay. After an ap-pearance at the Primary Patch Bay, a signal convertercompatible with the signal used by this multiplex is in-stalled to change the nonstandard tone signal to E&Mtype of supervision. These dc signals are converted tosingle frequency tones by a signal frequency unit; a

2-22

TM 11-5895-1012-10

Figure 2-85. TypicalTypical Voice Frequency Circuits (sheet 5 of 5)

2-23

TM 11-5895-1012-10

pulse link repeater may be required far transpositionof the E&M leads. Level control is maintained, as re-quired, by pads and amplifiers as indicated.

x. Four-Wire Entrance Toll Cable (Fig. 2-8 This circuit is required for interconnection at the Pri-mary Patch Bay with any long distance physical com-mercial toll circuit. Level adjustment using pads andamplifiers is located between the Primary and EqualLevel Patch Bays.

y. Four-Wire Connections to High Frequency RadioSystems (fig. 2-8 ). The remote high frequencyradio transmitter and receiver sites may access theTechnical Control Facility by either microwave radioor cable intersite links. Since the send and receivechannels are one-way and receiving combining is usedon the carrier telegraph system, all channels access thePrimary Patch Bay regardless of the intersite trans-mission media. Similar connections are made for thesechannels with pads and amplifiers for level adjust-ment, before the circuits access the Equal Level PatchBay.

2-18. Digital Data Circuits

Existing digital dc circuits consist of a wide variety ofmodulation rates, modes of operation, unit codes, andcircuit configurations. The variety of circuits and vari-ous equipment arrangements at the user end hascaused nonstandardization of dc Technical ControlFacilities.

a. Signal Levels. All dc circuits appearing at the dcEqual Level Patch Bay are configured for low-levelpolar operation.

(1) Only low-level operation is used within theblack patch, test, or conditioning equipment area with-in the TCF. Only low-level operation is used within ared equipment area when such an area is required tosupport the TCF. All teletype and data end equipmentused within the Technical Control Facility is config-ured for low-level operation in order to provide flex-ibility during equipment substitution and to facilitateconversion to encrypted operation at a later date.

(2) Unencrypted data orderwire and reporting cir-cuits may be required at some locations. These circuitsare intended for encrypted service at a later date andare configured and routed in-station so that instal-lation of the cryptodevice will not require major rewir-ing of the circuit.

b. Basic User Circuits. The total user requirementsare reducible to four basic types, allowing simplicityand standardization, at the digital dc patch panel andimprove efficiency. The four basic types of user-accesscircuits described below are shown in figure 2-9.

(1) Digital Data User-Access Circuits Via DcTransmission Mode. All user-access lines entering theTechnical Control Facility by way of the dc transmis-sion mode makes an appearance on the dc portion of

the Dc Primary Patch Bay. The signal from the Dc Pri-mary Patch Bay, if nonstandard or if isolation is re-quired, is converted to standard low-level and then ac-cesses the Dc Equal Level Patch Bay.

(2) Digital Data User-Access Circuits Via VFTransmission Mode. All user-access lines entering theTCF by way of VF transmission mode is treated as aVF circuit until converted to standard polar dc signals.The standard low-level polar dc then accesses the DcEqual Level Patch Bay. At this point the dc circuit iseither looped back to the local user or reconverted tovoice frequency for transmission over long haul trans-mission media.

(3) Technical Control Access Digital Data Cir-cuits. All TCF dc circuits (teletype orderwires, report+ing circuits, etc.) appear directly at the Dc Equal LevelPatch Bay.

(4) High Speed Data. All high speed (above 1200baud) dc circuits except those requiring coaxial typewiring access the Dc Equal Level Patch Bay directlywithout prior access through the Digital Line InterfaceUnit. All high speed dc line outputs and modems pmvide the standard low-level polar signal.

c. Timing, Control, and Alarm Circuits. Provisionsare made on the Dc Equal Level Patch Bay for patch-ing and testing of all timing, control, and alarm cir-cuits.

d. Testing of Dc Signals. All dc circuits appear atthe Dc Equal Level Patch Bay. Dc signals whichappear at the Dc Primary Patch Bay will differ in cod-ing schemes and baud rates. Testing of all dc circuitswill be performed on a high impedance basis. Signallevels applied to the high impedance test equipment inall cases are equal no matter what the coding schemeor baud rate.

2-19 . Wideband Fac i l i t i e s(fig. 2-6)

a. General. Facilities for monitoring, testing, andpatching of wideband circuits, multiplex groups,supergroups, and basebands are provided at stationswhere required as outlined below. Wideband jack-fields, in bays separate from VF and dc jackfields areprovided for this purpose.

(1) Wideband circuit monitoring and testingfacilities are provided at all stations which controlsuch stations. At stations where alternate routes orspare equipment for such circuits are available, patch-ing facilities to permit reroute or restoral is also in-cluded within the TCF.

(2) Group, supergroup, and baseband monitoring,testing, and patching facilities are provided at all sta-tions having more than two multiplex link terminals,and are sometimes provided at smaller stations tomeet special requirements. Normally, at stations hav-ing only one or two multiplex link terminals, the jack

2 - 2 4

TM 11-5895-1012-10

Figure 2-9. Standard dc/data access circuits

multiplex equipment is adequate

rgroup, and Group Patching Con-

(1) The capability for patching among like and un-

of group or supergroup connectors is required.t which use the standardbut have different levels,ncies can be made compat-

through the use of con-certain types of multi-use nonstandard fre-

y allocation plans and therefore cannot beed at the group or supergroup level even with. .

Appearances for such equipment may bewideband jackfields for monitoring and

testing only.(2) DCS standard levels and impedances for

group, supergroup, and baseband have beenestablished. However, them are still types of multiplex

equipment in use which have been designed to operateat other levels and impedances. In stations wheremultiplex not conforming to DCS standard levels andimpedances exists or is programmed for installation, alocal standard is established. The term standard whenused in this manual refers to that standard which is inuse, either the DCS standard of local standard of levelsand impedances.

(3) A stand&-level jackfield is provided. It in-cludes appearances of groups, supergroups, and basebands of all multiplex equipment operating at thestandard levels and impedance, group and supergroupconnectors designed to operate at those levels and im-pedances, and one end of each conditioning string.

c. Conditioning Chains or Strings. Conditioningequipment chains or strings are usually made up of thefollowing types of components. Not all components arerequired for every string. Only those componentsnecessary to match the levels, impedances, and pilotfrequencies of a particular type of nonstandard multi-plex to the station standard is included in each string.

(1) Impedance matching equipment is required to

2-25

TM 11-5895-1012-10

match a variety of impedances encountered in dif-ferent types of multiplex equipment, including 600,150, and 135 ohms balanced and 75 ohms unbalanced.Not all of these will ordinarily be found in the samestation.

(2) Level adjusting equipment is used to co-ordinate the levels of groups, supergroups, and base-bands of nonstandard multiplex with the standardlevels. This equipment includes adjustable attenuatorsand wideband amplifiers. The impedance matchingfeature described above may be combined with the at-tenuators or amplifiers or both in integrated as-semblies.

(3) Group pilot frequency conversion equipmentis used to change nonstandard group pilot frequenciesto the standard frequency without change in level.This equipment removes the incoming group pilot,converts it to the desired frequency, and reinserts it atthe same level as the incoming pilot. The reinsertedpilot level will track any variations in the incomingpilot level with an accuracy of ±0.5 dB. Pilot alarmequipment to indicate variation in pilot level beyondallowable limits is usually associated with the fre-quency conversion devices.

2 - 2 0 . I n t e r n a l S y s t e m s

Systems internal to the TechnicalFacility include all of the nontraffic handling

subsystems, which include but not necessarily limitedto those described in the following paragraphs.

b. Intercommunications (Intercom) System. Theintercom system provides technical coordination in-ternal to the Technical Control Facility and to supporting and using agencies located in the vicinity of theTCF Intercom service is provided through the use ofexisting administrative telephone circuits which con-tain the intercom feature, and through the applicationof a multistation intercom system. The intercom sys-tem shares common equipment and operator panelswith the orderwire system. The number of intercomstation locations varies with the operational missionand actual TCF configuration. The audio and dc patchbays are equipped with a sufficient number of inter-com stations to allow access from each workinglocation. As a minimum, one intercom station is provided for every three patch bays.

c. Alarm System. An alarm system is provided toalert the Technical Controller and maintenance tech-nicians of equipment degradations or failures that af-fect communications circuit status. Information prosented by the alarm system initiates prompt actiontoward the restoration or rerouting of circuits and therepair of faulty equipment. Display of alarms is in acentral location provided in the Technical Control Fa-cility operating area. Parallel presentation of portionsof the alarm display is also required in maintenance

and operating areas remote from the(supervisory. maintenance, or service areas). Theamount and type of equipment necessary to satisfythis requirement is dependent on the TCF size and willvary from site to site.

(1) All alarm outputs are accessible at the mainframe. According to equipment types, alarms are des-ignated as “go-no-go” or analog types (for adaptation tmore sophisticated monitoring). The alarm display ixcludes but is not limited to the following as applicableto the station configuration:

(a) All radio paths.(6) Cable carrier systems.(c) Data circuits.(d) Circuits having an alarm feature.(e) Common equipment units which could affect

service.(f) Low transmitter output.(g) Low receiver input.(h) High received noise on the radio channel.(i) Failure of standby equipment.(j) Failure of primary equipment.(k) Signal level, high or low.(l) Power being used <primary, secondary

emergency, auxiliary, or battery).(m) High or low power voltage.(n) Open fuse alarm.(o) High or low pilot frequency level.(p) Failure of line signalling supply.(q) Low fuel supply for generator.(r) Open door or window (at unattended

station).(s) Failure of obstruction or warning light.(t) Change in waveguide pressurization.(u) Fire in equipment area.(v) Failure of environmental control system.

(2) The alarm system provides for incremental espansion. The system is usually so designed that activa-tions, deactivations, and changes of transmission sys-tems, TCF subsystems, and circuits can be ac-commodated without affecting the operation of thebasic system. The system is usually broken down intotwo subsystems:

(a) A local equipment and functions alarm sub-system.

(b) A remote station equipment and functionalarm subsystem.

d. Orderwire System. An orderwire network is pro-vided for efficient TCF procedures. Informationregarding circuit and facility statuwork, and maintenance and trouble comitted over this network. Voice and daup the orderwire network and providmeans of coordination between two ortween a TCF and associated PTF, andand some special communicati use

2 - 2 6

TM 11-5895-1012-10

a. Types. Different types of cabling are necessaryfor interconnection of the various equipment and key-ing lines with the Primary and Equal Patch Baysas well as the transmission media equipment and sub-scribers.

and type of orderwire circuits required at TCF's varyfrom site to site as dictated by station size, mission,and location.

2 - 2 1 . S t a t i o n

(1) Voice frequency lines generally use appropri-ate sizes of shielded, single pair wires.

(2) Direct current keying lines use individuallyshielded pairs.

(3) Standard power cables are used to distributeprimary power to equipment

(4) Coax and twinax are used for high speed dataMODEMS.

b. Routing. Cables are usually installed in one or acombination of the following four methods; overheadinclosed ducts, overhead open racks, cellular flooring,and floor trenches.

c. Shielding. Prevention of mutual interference be-tween circuits that carry dc keying signals and circuitsthat carry vf signals is accomplished by shielding thedc keying circuits. Whenever feasible, separate racksor ducts should be used for each type of circuit.

2-22. Distribution Frames

a. All in-station lines, equipment and channels, plusexternal cable pairs, terminate on a distributionframe. A main distribution frame is used for terminat-ing outside lines and an intermediate distributionframe is used to terminate in-station lines. However,in the interest of simplification and conservation ofapace it is common practice to use a combined distri-bution frame within the Technical Control Facility.The distribution frame is made up of vertical andhorizontal terminating blocks. The vertical blocks,used for terminating outside lines, are provided withprotective devices to shield the cables and associatedequipment from high voltages surges. The horizontalblocks are used to terminate the in-station cabling.Cross connections are made on the distribution frameto obtain the desired circuitry.

b. Jack appearances, in the Primary and EqualLevel Patch Rays, are terminated on the combineddistribution frame as are the equipment associatedwith collocated facilities.c. Temporary arrangements of circuits and equip-

ment can be provided in the patch bays with the use ofpatch cords. However, all permanent changes shouldbe made on the combined distribution frame in orderto minimize the requirements for patch cords in use atany time in the Technical Control Facility.

2-23 . Power Fac i l i t i e s

d. All cable runs and equipment connections are

made to provide transmission security. The criteria arebased on the concept of separation of red and black cir-cuitry within the TCF and the DCS Station. In order toaccomplish this separation, there are two separatedistribution frames provided. One to carry the red cir-cuits and the other to carry the black circuits.

(1) Red Frame. The red frame is used to makecrossconnections between red circuits, patch panels,and equipment, Red circuits are those circuits whichcarry or are cleared to carry, clear text, classifiedtraffic. The red frame has a horizontal aide and avertical side like any other combined distributionframe. Termination blocks are mounted on both tidesof the red frame. The vertical side is used to terminateequipment, such as relay center equipment (send andreceive); the clear side of the COMSEC devices (sendand receive); the red side of battery isolation relays(send and receive); and for red circuit control, switch-ing, or monitoring devices. The horizontal side is usedto terminate the red patch panels and the positive andnegative rectifiers used to furnish battery. If anytraffic-carrying circuits which are approved forhandling clear text classified traffic without COMSECdevices are in use, the lines will be connected to thevertical side of the red frame. The cables which areused to connect the items listed above to the red frameare permanently connected to the left side of the ver-tical blocks and to the bottom side of the horizontalblocks. Cross-connections are made as required to con-nect battery, equipment, patch panel jack appear-ances, and COMSEC devices together to form a circuit.

(2) Black Frame. The black frame is used to makecross-connections between black circuits, patch panels,lines and equipment. Black circuits are those circuitswhich carry encrypted traffic or unclassified, cleartext traffic. The black frame is the same configurationas the red frame, having a horizontal side and a verti-cd side. The horizontal side is used to terminate theaudio and dc patch panels of the TCF and the positiveand negative battery supplies. The vertical side is usedto terminate the following items: all landlines, bothaudio and dc; the black or encrypted side of COMSECdevices; the black side of battery isolation relays; andany black circuit control, switching, or monitoring de-vices used in the TCF. The various items are cross-con-nected as required to form the desired circuitry.

a. General. Each Technical Controller must beaware of power facilities used to provide primary andauxiliary, and emergency lighting power at the DCSStation. A detailed discussion of power facilities andequipment is given in paragraphs 2-24 through 2-28.

b. Primary Power. The term primary power is usedat DCS Stations to denote the primary ac power sourceto the DCS Station under normal operating conditions.

2 - 2 7

TM 11-5895-1012-10

c. Auxiliary Power. Auxiliary power is provided ateach DCS Station to replace all or part of the primarypower in case of failure. This auxiliary power is usuallysupplied by engine-generators and storage batteries.These engine-generators are installed and operated aspart of the DCS Station. Auxiliary power is thecurrently-approved designation for back-up or altern-ate power sources frequently referred to as emergencypower sources.

d. Emergency Lighting Power. Emergency powerrequirements at DCS Stations are normally limited tobattery-powered lighting systems for use whileauxiliary power equipment is being activated afterfailure of the primary power supply. These emergencysystems are normally automatically activated im-mediately upon failure of the primary or auxiliarypower supply, and are removed from service as soon asprimary or auxiliary ac power is restored.

2-24 . C las ses o f Power

Station power is divided into four classes as follows:a. Class A Primary Power. A primary power plant

which provides an essentially continuous supply ofelectrical power.

b. Class B Auxiliary Power. A standby power plantto cover extended outages (usually days in length) of aprimary power plant.

c. Class C Auxiliary Power. A quick start (10 to 60seconds) unit(s) to cover short-term outages (usuallyhours in length) of a primary power plant.

d. Class D Auxiliary Power. An uninterruptible (nobreak) power unit(s) using stored energy to providecontinuous power within specified voltage and fre-quency tolerances.

2-25. Types of Ac Power

AC power is available in many different forms (voltage,phase, and frequency). The type required by a particu-lar DCS Station is determined by the equipment in-stalled at that DCS Station.

a. Frequency. All ac powered communicationsequipment manufactured in the United States is avail-able in models that require an input frequency of 60-Hertz (Hz). Some equipment is also available in modelsthat can operate on ac power supplied at different fre-quencies, such as 25 or 50 Hz. Most foreign-madeequipment is designed to operate only from 50 Hzpower sources. Since most of the equipment at anyDCS Station will be manufactured in the UnitedStates, the primary ac power source should be 60 Hz.So that equipment designed for other frequencies canbe operated, a rotary or solid-state static type con-verter is used to change the frequency of the primarypower.

b. Voltage. Most communications and test equipment is designed to operate on 120 volts single phase.

However, equipment that requires large amounts ofpower, such as a high-powered radio transmitter,generally is designed to operate on 240 or 480 volt,three phase power. These are nominal voltages, and avariation of ±5 percent usually can be tolerated.

(1) Some equipment is built with power inputtransformers, that have tapsbrought out to terminals.These taps are on the primary (input) side of the trans-former, and are marked with a common voltage value.For example, a transformer in a piece of equipmentmay have-either three or five taps. If there are threetap, they usually are marked 105, 115, and 125 volts;if there are five taps, they are usually marked 105,110, 115, 120, and 125 volts. Transformers for higher

(2) Three-phase power requirements at DCSStations are usually at a nominal 120/208 volt po-tential. However, some RF power amplifiers etc., maybe designed to operate on different voltages, such as240 or 416 volts. These voltages are supplied byspecial transformer configurations.

c. Phase. Equipment that requires 120-volt inputpower is generally designed for single-phase powermost equipment that requires 240-volt input power isdesigned for three-phase power. The generation ofthree-phase power is accomplished by three separateinduction coils in the generator. The method ofconnecting these three coils results in variousconfigurations, and may be arranged to give differentvoltages in the range of 208 to 480 volts. The three-coils, and the individual phases they produce, areseparated by 120 degrees so that there is equality be-tween the three phases. Higher powered generatingplants normally produce three-phase power. Themajority of the DCS Station equipment uses onlysingle-phase power. Distribution of primary powerwithin the station is important; therefore, disparitybetween loads on individual phases creates problemsand should be balanced within reasonable limitations.

2 - 2 6 . G e n e r a t i n g E q u i p m e n t

a. General. The engine-generator sets provided atthe DCS Stations are used for primary or auxiliarypower requirements. For use as either a primary powersource or an auxiliary power source, the electricalcharacteristics are the same. Normally, the only dif-ference is that more sets of equipment are required ifthey are used to produce power at all times. Forexample, the general practice for auxiliary power is toprovide two complete sets of power generating equip-ment. When they are used to provide all power for thestation, at least three complete sets of equipment arerequired.

b. Engines. The engine, or prime-mover is designednave more horsepower than the generator rating;

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this provides for losses and the capability to maintainconstant speed at full load. The engine must also beequipped with a governor to maintain a constant out-put when the generator is connected to a varying load.Diesel and gasoline engines are used as prime movers.

(1) Diesel Engines. Both low-speed and high-&diesel engines are used as prime movers. High-speeddiesel engines can be installed at less cost than the low-speed, heavy-duty diesel engine, but not operated ormaintained as economically.

(2) Gasoline Engines. Gasoline engines are used asprime movers to drive generators of limited capacityto supply power on an intermittent or purely auxiliarybasis. They should not be used to drive generators tosupply power continuously or over extended periods oftime, because the useful life of a gasoline engine incontinuous service is relatively short. The initial costof a gasoline engine is much less than that of a dieselengine, but maintenance costs are higher.

(3) Gas Turbines. Gas turbines have the advan-

tages of light weight, quick starting, and acceptance ofload without the usual warmup period. A disadvantageis their high fuel consumption rate.

2 -27 . Power Di s tr ibut ion

a General. As previously indicated, most DCSStations have at least two separate power sources, pri-mary power and auxiliary power. These two powersources must be selectable; that is, switching and othernecessary mechanisms must be provided to permitstation personnel to select the desired source. Change-over must be fast, in fact, it should be possible tochange power sources without any break in the powersupply to the communications equipment. When pri-mary power fails without warning, this may not bepossible, but activation of the auxiliary power and con-nection to the communication should comply with theprescribed standards. In addition to the power change-over requirements, normal operation requires that thepower demands within the station be balanced amongthe phases of *phase primary power supplies.

b. Switchboards and Automatic Transfer Panels.

EL3Z0055Figure 2-10. Double bus arrangement and automatic transfer panel, wiring diagram.

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Automatic transfer panels provide an automaticswitching arrangement designed to maintain powerwith minimum interruption for the operation of DCSStation equipment. Transfer panels must handleseparate sources of power. In the case of a combinationof generators, or of generators and commercial power(fig. 2-10). the desired power source can be selected topermit rotation of the engine-generators. A time-delayrelay will postpone switching the load to any engine-generator until the engine reaches its recommendedoperating temperature. If there is a gradual decreasein voltage, voltage-controlled relays will switch theload to an alternate source of power.

c. Station Power Panels. The main power distri-bution panels are determined by the individual stationrequirements. When two or more power sources areoperated in parallel, a master control switchboard provides a means for measuring the output frequency,voltage, and current. These measurements generallyare made at the main bus bars, and thus indicate thetotal load and combined power supplied.

d. Distribution for DCS Stations. DCS Stations re-ceive power from an external distribution system orlocal Class A primary power plant. Distribution withinthe DCS Station begins at the main power panel andextends to the operating equipment. Subpanels, trans-formers, and circuit breakers may be included in thedistribution circuits. Communication equipment in thestation may he divided into two or more major groups.Each major group of equipment is connected to themain power panel. Radio transmitting stations havethe largest and most complex power installation of theDCS. The output voltage and the configuration ofengine-generators is connected to transformers, ordirect& to the bus bars on the main switchboard.Distribution lines from the power panel to operatingequipment are installed in floor trenches, in ducts, oron cable racks.

e. Simplified Power Distribution. The following is adescription of the simplified power distribution shownin figure FO-1. Many different arrangements arepossible at all stages, and each station’s requirementswill determine the best arrangement for the particularinstallation.

(1) Primary power at 2400 volts is available fromthe commercial power source or from either of the twogenerators installed at the station. At the main switch-board, located in the utility building with the gen-erators, power from any one or more of these sourcescan be applied to either or both of the power distri-bution cables to the operations building. In thisexample, all switching is performed at 240 volts, afterreduction by deltadelta transformers. In some cases,these switching functions may be performed at the2400-volt level and the transformer located in theoperations building.

2-28. Uninterruptible Power Supply(UPS)

(fig. 2-11, 2-12)

2 - 3 0

TM 11-5895-1012-10

generator load and cranks the diesel engine with aminimum drop in frequency during the transition.

After the diesel engine comes up to speed, it assumesthe load and continues to produce power to meet the

load requirements. During diesel operation, the com-mercial power is constantly monitored for voltage andfrequency. When the commercial power returns to thecorrect voltage and frequency, normal operation isresumed, that is the commercial line contractor closes,the magnetic clutch is deenergized, and the diesel

engine shuts down after a cooling-off running period.The electric motor and flywheel continue to operate.Figure 2-12 shows the unit in standby operation andfigure 2-13 shows the unit online.

b. Another method for providing uninterruptiblepower which is being utilized in overseas AUTODIN atthe Automatic Digital Message Switching Centers(ADMSC’s) is shown in figure 2-13. This type of a UPSmay also be found at DCS Stations other than thosecollocated with an ADMSC.

Figure 2-11. Uninterruptible power supply in standby condition.

Figure 2-12. Uninterruptible power supply in on-line condition.

2 - 3 1

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Figure 2-13. ADMSC uninterruptible power system.

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(3) The battery bank consists of 120 2-volt single-cell units connected in series.

(4) There are four motor-generator units operat-ing at any time, but a total of five units are availablefor operation. In case one of the operating units fails,the standby unit is automatically turned on,.synchronized, and switched on the line within 10 sec-onds. The UPS is designed so that, under normal op-erating conditions (four units on-line), each M/G set isoperating at approximately 60 percent of rated load.Since the units are rated for a 25 percent overload lasting at least two hours, the UPS system is capable of op-erating with only two functioning M/G sets for briefperiods, and with three sets for indefinite periods.This degree of redundance provides the critical por-tions of the ADMSC with great reliability.

(5) Under normal operating conditions, four M/Gsets are connected to the critical supply bus and areequally dividing the system load within their normal

Based on these normal system operating con-an automatic power load transfer is accom-

at the no-break critical supply bus as a result ofone or more of the following abnormal operating sys-tem conditions:

(a) Variation of generator output voltage be-limits of plus or minus 10 percent of normalue of 120/208 volts (sensed by the over and

utput frequency be-/2 Hz of the nomi-

and over frequency

flow as sensed by

(6) The following controls are built into the UPSto maintain the stabilized power required for theADMSC:

(a) Frequency Regulation. The magnetic ampli-fier type of speed regulator is provided with the dcmotor of each motor-generator unit for controlling theM/G set speed, which in turn controls the output fre-quency. These speed regulators offer the advantages ofhigh corrective output signal (high gain) from arelatively low level input with associated fact responseto variations in the M/G set speed (frequency). Thespeed regulating system consists of a frequency detec-tor, magnetic amplifier control circuit, and a singlephase full-wave magnetic amplifier which controlsexcitation of the dc motor.

(b) Voltage Regulation. The generator outputvoltage of each motor-generator unit is controlled byan individual magnetic amplifier type of voltageregulator.

(c) Additional Controls. In addition to the abovecontrols, each motor-generator set contains associatedunder and over voltage relays, and reverse current re-lays to monitor operation properly. Activation of anyof these relays will energize the trip circuits of the in-put and output circuit breakers and remove the as-sociated M/G set from the UPS system.

c. Another method for providing uninterruptiblepower to critical loads is the solid-state static-typerectifier-charger-battery-inverter system shown by thesimplified system block diagram in figure 2-14. Thisis a modularized redundant system each module con-sisting of a rectifier-charger unit, a battery (usuallyselected for 15-minute output), and an inverter unit to-gether with appropriate protective devices. Each mod-ule has a 100 kilowatt (KW), 125 kilovolt-ampere(Kva) output rating.

(1) The unit is designed for 200 kilowatt output.Normally the 200 kilowatt rated load is divided equal-ly between the three 125 Kva units. In case of failureof any one unit, the unit that has malfunctioned isautomatically removed from operation and the 200K W load is divided equally between the two remainingunits. Being modular constructed, the module thatfailed can be de-energized, the trouble located, and anew component inserted in the circuitry.

(2) Since this type of UPS has limited operatingexperience, records of performance so far have indi-cated a mean-time-between-failure (MTBF) to be antic-ipated on the order of 80,000 hours.

2 - 2 9 . M i s c e l l a n e o u s P o w e r E q u i p m e n t

a. Storage Batteries. Storage batteries provide acompact source of dc power for the operation of equipment requiring a dc source with a DCS Station.

b. Dry Batteries. Dry batteries are used by DCS Sta-tions to furnish power for certain alarm circuits, emer

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Figure 2-14. Solid state uninterruptible power system, simplified block diagram.

gency signal lights, test equipment, etc. These bat-teries are available in various sizes and shapes and inseveral capacities and voltages to accommodate a widerange of uses. Special purposes dry batteries of higherthan normal quality are also available for certain ap-plications.

c. Rectifiers. With an ac power source, rectifiers inconjunction with appropriate transformers and filtersyield dc power with very little ripple content. Twocommon types of rectifiers are those that use electrontubes and those that use semi-conductors of the disktype (selenium, silicon, and germanium) as the rectify-ing medium. Some rectifiers are designed as part of aspecific equipment and some of these cannot be used inother applications. However, many general purposerectifiers are available. In efficiency, rectifier output isusually from 60 to 70 percent of the input power.

d. Dynamotors. Dynamotors are rotating machinesused to convert dc voltage of one value to dc voltage ofanother value and usually are components of specific

equipment Usually, these units have only one setfield coils and each set of armature windings is connected to its own commutator. Essentially, dynamotors are motor-generators in which the motor andgenerator windings are wound in the same slot and ona single common armature.

e. Frequency Changers.(1) Frequency changers are motor-generator sets

that convert ac of one voltage and frequency to ac ofanother voltage and frequency. Frequency changersare used in DCS Stations to convert the incoming asfrequency and voltage to match the input power requirements of certain items of DCS equipment.

(2) The motor-generator sets, depending on theapplication, may be driven by either a single or mullphase induction or synchronous type motor. The driv-ing motor is usually coupled directly to the generatorby a common shaft with both machines mounted onthe same bedplate.

Section IV. REPRESENTATIVE TCF EQUIPMENT

2-30. General

introduction of high-speed datatransmission into the DCS, the term “circuit condition-ing” was little used in Technical Control Facilities. Ashigher speed data circuits came into wider usage, theterm became increasingly familiar to technical control-lers, especially as it applied to circuits obtained from

have an understanding of the requirements for circuitconditioning and technical information on the equip-ment required fop circuit conditioning. This section

will discuss the conditioning equipment found in theTCF and those other items of equipment which are re-quired to insure circuit performance and to enable theTechnical Controllers to perform the function of theTCF.

b. Ideally, all transmission systems and the chan-nels of these systems should preserve the fidelity anamplitude of the original information. However, it isrecognized that in a practical communications systemthe information carried over any transmission mediais subject to certain electrical characteristic changeswhich result in loss, delay, or distortion of the trans-mitted information. Even though systems are properly

2 - 3 4

in electrical characteristics requiringconditioning equipdistortion, envelope

delay, signal level changes, and longitudinal balance.

2-31 . C i rcu i t Cond i t ion ing Equ ipment

The following is a brief description of circuit conditionequipment used on the DCS and found in the TechnicalControl Facility.

a. Pads. Pads, which come in many forms and physi-cal arrangements, are used to attenuate signals withina circuit. Pads found in telecommunications normallyhave the same input and output impedance; however,they can be designed to match impedance of differentvalues. The attenuation introduced by a pad is varia-ble, most usually by using different strapping optionsto adjust the amount of attenuation in steps of 0.5 dB.

b. Amplifiers. An amplifier is used to increase sig-nal strength without introducing appreciable distor-tion and to compensate for attenuation of signals on vfchannels. Transistorized and vacuum tube amplifierswill be found in use on the DCS. Typical amplifiersused in circuit conditioning have an adjustable gain offrom zero to 35 dB at 1000 Hz, stabilized within ±.2dB and with a frequency response from 300 to 3400Hz. Input and output impedances are usually 600 ohmsbalanced.

c. Amplitude Equalizers.(1) Decreased intelligibility in voice circuits can be

caused by the unequal attenuation of different fre-quencies. For example, as various frequencies passalong a nonloaded cable, the high frequencies are at-tenuated more than the lower ones. A l-mile section of26-gauge high-capacity cable will have a loss of about1.4 dB at 250 Hz; however, at 3000 Hz, the loss will be4.5 dB, a difference of 3.1 dB per mile. Therefore, a 4-mile section of 26-gauge nonloaded cable will result ina 5.6 dB loss at 250 Hz and an 18.0 dB loss at 3000 Hz.The 1000 Hz loss of the 4-mile loop would be 10.7 dB.The loss across the band, taken at these three fre-quencies referenced to the 1000 Hz loss, would be 5.1dB less loss at 250 Hz and 7.3 db more loss at 3000 Hz.

(2) The variation in loss across the band of in-terest can be compensated for by equalizing. Theequalizing process consists of inserting into the circuitadditional loss which varies with frequency. Sufficient

is added at each frequency to bring the responseacross the band within a specified limit referenced tothe loss at a specified frequency, usually 1 kHz.

(3) The amplitude equalizer is any combination ofcoils, capacitors, or resistors inserted in transmission

TM 11-5895-1012-10

or amplifier circuits to compensate for differences inattenuation due to differing impedances at the variousfrequencies being used. Adjustments are usually pro-vided to accomplish the required equalization.

d. Envelope Delay Equalizers.(1) There is still another way in which voice-grade

circuits can vary with frequency, and that is in thevelocity of propagation. This variation does not usual-ly affect speech transmission, but it can have an ad-verse affect on data transmission.

(2) In any circuit there is a finite time interval fortransmission from the sending end of the circuit to thereceiving end. This time is referred to as absolute de-lay and varies according to the facility used. This timeinterval will also vary considerably between variousfrequencies in the transmitted band. This means thatthe shape of a signal wave at the receiving end can dif-fer to an appreciable degree from that originally ap-plied at the transmitting end. This distortion is calledenvelope distortion; and it is measured in microsec-onds of envelope delay.

(3) Envelope delay distortion is the result of thedeviation of the phase shift from a straight line pat-tern across the frequency band of interest. In carriersystems, the variation in time and frequency is causedmainly by the channel filters. Often additional distor-tion will be found in the outermost channels of a car-rier group. This effect will be more noticeable in somesystems than in others and is caused by the filter cut-off. Normally, it is good practice to avoid the lowerand upper channels of a group or channels adjacent topilot tones when channels are being assigned for dataservice.

(4) Although delay distortion is found in cable andchannel terminals, it should be remembered thatequipment units, such as repeaters and coils, alsocontribute to delay distortion. These units affect thefrequencies below 1000 Hz to a greater extent thanthose above 1000 Hz. In calculating the overallenvelope delay of a circuit, the delay inherent in eachequipment unit or line facility section, at specific fre-quencies, is summarized. When the delay of theequalizer is added to that of the equipment and facil-ities, the result should be within the limitations for thecircuit being implemented.

(5) For individual circuits which will be switchedin tandem to form a completed connection, the delayrequirements are much more stringent than for theoverall connection. It is necessary, therefore, that eachcircuit, whether an interswitch circuit or access line,fall within the delay distortion limits establishedunder the transmission plan for the system involved.This limit will be stated in the Circuit Layout Record(CLR) Card for the circuit.

(6) There are two general types of equalizers usedto compensate for the effects of envelope delay. One of

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these is often called “passive” equalization and theother "active” equalization. Passive equalization is gen-erally used when referring to circuits where fixedequalizers are inserted after the required value is com-puted. Active equalization is commonly used through-out the DCS since such equalizers are continuouslyvariable over wide ranges and may be simply adjustedby Technical Control Facility or maintenancepersonnel.

(7) Either method of equalization ignores theabsolute delay and only equalizes the relative delay.Delay equalizers consist of a series of networks withdelay characteristics inverse to those of the circuitking equalized. Each adjustable section provides suf-ficient time delay in its frequency band to reduce therelative delay distortion. One unit in common use inthe DCS reduces the relative delay distortion from 3milliseconds to less than 80 microseconds from 1000to 2000 Hz, to less than 260 microseconds from 200 to1000 Hz, and to less than 500 microseconds from 500to 600 Hz, and from 2600 to 2800 Hz. It is importantthat delay equalizers, particularly passive equalizers,be placed adjacent to a constant impedance attenuatoror a 600 ohm pad to ensure proper impedance termina-tion.

e. Repeat Coils. A repeat coil is essentially a trans-former which will transfer electrical energy from onesource to another without metallic connection betweenthe circuits. For direct current purposes, it divides thecircuit into two portions. It was from this transferfunction that the term “repeating coil” was originallyderived, since it was used primarily to repeatinformation, rather than change voltage or currentvalues as in power systems. Repeat coils are usuallythought of as impedance matching devices, and the useof the proper ratio coil is a basic consideration in cir-cuit design

f. Echo Suppression(1) Echo. A problem, peculiar to long circuits that

terminate in 2-wire instruments, arises from thevelocity of propagation of the various facilities usedfor telephone communications. The time required forthe transmission Of voice signals from one point to adistant termination will vary according to the type offacility and the overall length of the circuit. If, when aconversation is being carried on, some part of thespeaker’s voice is returned to him from the distant ter-mination, and the time involved is of sufficient dura-tion, the returned voice signal will have the effect ofan annoying echo.

(2) Echo Tolerance. On circuits that are physicallyvery short, currents return in such a short period oftime that they take the form of sidetone, which is notobjectionable to the talker. As the time interval in-creases, currents returned at the same level assumethe form of an echo and become objectionable. Since

switched 2-wire PBXtion lines will not besince they do not havegenerate the echo.

g. Telegraphtronic devicessynchronous othem prior to retransmission. They are usually con-structed to accept various modulation ratescept signals with uperative repeaters arefor telegraph circuits,included as part of original circuit design and a con-tinuing requirement for their use generally indicatescircuit or equipment malfunctions which should be lo-cated and corrected and the regenerator removed fromthe circuit.

h. Data Modems. This term is a contraction fromthe terms modulatordemodulator and all of theseunits, which are in use in the DCS in many forms andconfigurations, perform the same purpose. They con-vert digital signals to an analog form in the modulatorportion and convert analog information into digitalform in the demodulator portion. In certain specialcases two modems are used on a back-to-back arrange-ment to provide regeneration for data circuits. In thisarrangement the output of one modem will be put intoanother modem of the same type which will in turnprovide a reshaped and retimed output.

2 - 3 2 . W i d e b a n d C o n

a. Wideband condiegories, the first covering that condition required forthe interconnection of voice frequency multiplexequipment with different characteristics; the secondfor the special conditioning required for 48 kHz chan-nels utilized for wideband data or secure voice trans-missions. The standard parameters for voice frequencymultiplex, frequency division (FDM) which have beenestablished for equipment used in the DCS are:

(1) -34.5 dBr send level input.(2) -12 dBr receive level output.(3) 135 ohm impedance (balanced) for both input

and output.(4) 104.08 kHz pilot.

b. Any new vf FDM must operate at the

2 - 3 6

a considerable number of FDM terminals in use in theDCS which do not utilize the standard parameters.When interconnection at the group or supergroup levelis required between this nonstandard equipment orstandard to nonstandard equipment special condition-ing equipment is required between the multiplexersfor the purpose of level compatibility and impedancematching. This conditioning equipment is connectedin the same manner circuit conditioning equipmentwould be connected on the circuit level.

c. Nonstandard multiplex equipment in use in theDCS generally does not utilize the same pilot fre-quency as that used in the standard parameter (104.08kHz). When multiplex utilizing different pilot fre-quencies must be interfaced at group or supergrouplevels, pilot conversion is required. This process is re-ferred to as pilot stop and reinjection. Suitable equipment must be provided which will stop the unwantedpilot frequency and permit insertion of the requiredpilot frequency. Equipment which perform these func-tions are commonly called pilot stop and reinjectionfilters, and are especially designed for interface at thepilot frequencies of the multiplex terminals.

2-33. Other Conditioning Equipment

Technical Control Facility personnel will be requiredto be familiar with the operational and technical char-acteristics of other ancillary equipment which may berequired to assure proper operation but which are notusually referred to as conditioning equipment.

a. Four to Two-Wire Terminating Sets. The four totwo-wire terminating set is used between a two wireVF channel and a four-wire VF channel. It converts‘the two wires used for transmit-receive to two wiresfor transmit and two wires for receive. Usually the ter-minating sets also provide impedance matching facil-ities, enabling 600-ohm 4-wire circuits to be con-nected to 600- or 900-ohm 2-wire circuits.

b. 600-Ohm Terminations. The normal terminatedimpedance of lines used in telephone work is 600ohms, although some 900 ohm terminations may beused. When the equipment normally used to provideproper termination is removed, the Technical Control-ler must have available a rapid method of terminatinglines so that any test measurement made on the linewill be accurate. A device in common use in TechnicalControl Facilities is a terminating resistor which isusually a noninductive resistor of the proper valuewired across plugs of the same type as those used atthe patch panels.

c. Data Conferencing Network. This device (alsoknown as a Technical Control Facility Hubbing Re-pester) enables a predetermined group of users to oper-

TM 11-5895-1012-10

ate such that if any one user transmits a message, it isreceived by all others in the group. The network allowsany user to transmit as long as only one station istransmitting at any particular moment. The hubbingrepeater may be used as the interface device between aSend Only device and several receiving terminals.

d. Passive Peak Limiter. This unit is used to auto-mat&By prevent system overload causes by excessivetransmission levels from the user equipment Thisequipment is located on the equipment side of theEqual Level Batch Bay within the conditioning stringon audio channels.

e. 6-Way 4-Wire Bridge. This unit provides a con-ferencing capability for 6 each 4-wire telephone cir-cuits.

2 - 3 4 . S i g n a l i n g E q u i p m e n t

The signaling equipment in the Technical ControlFacility provides the means of interfacing ringing anddial pulse signaling between two different cross-con-nected channels. The equipment is also used to changethe signal from out-of-band signaling to in-band sig-naling. Various types of signaling equipment is dis-cussed below.

a. Single Frequency Signaling Units (SFSU). Thisequipment is used when it is necessary to convert fromE&M signaling to in-band 2600 Hz or 1600 Hz signal-ing or in-band to E&M signaling. The SFSU transmitsection converts dc-dialing or supervisory signals pres-ent on the M-lead into an amplitude-modulated tonefor transmission over voice frequency channels. TheSFSU receive section converts received amplitudemodulated tones into dc-dialing or supervisory signalson the E-lead. The state of the E&M leads may begrounded, +48 vdc, or open circuited. The normalE&M logic is as follows:

(1) Central Office Dial Loop to E&M Converter.This unit receives 20 Hz from the central office andconverts it to an M-lead seizure for input to an SFSUin the outgoing direction, and presents a closed loop tothe central office when the E-lead from the SFSU in-dicates an incoming call.

(2) User Dial Loop to E&M Converter. This unitrecognizes a closed loop when the user goes off-hookand indicates seizure to the M-lead and converts dialpulses to M-lead pulsing of the SFSU. When a call isincoming to the user the E-lead causes a 20 Hz ringingsignal to be sent to the end instrument.

2-37

b. E&M/Loop Converter (E&M to Dc). The dial loopto the E&M converter provides complete access between a central office and a dial user instrument over avoice frequency carrier channel. There are two ver-sions of this unit as follows:

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lead when a signal is received from the ringdowntrunk circuit. It also receives signals over an E-leadfrom a signaling circuit and transmits 20 Hz signals toa ringdown trunk circuit. This equipment can be ar-ranged to operate with signaling frequencies otherthan 20 Hz when required.

d. E&M Signal-Lead Extension Circuits (DX1 andDX2). These signal-lead extensions units are designedto interconnect two signaling and supervision circuitswhen the metallic resistance between users exceedsoperational limits. They are also used to interconnectan E&M signaling circuit to a distant trunk circuitwhich uses single frequency signaling. E&M signal-lead extension circuits are usually required where theconnecting facility (cable) resistance exceeds 25 ohms(50 ohm loop). These circuits, which have been codedDX1 and DX2, are always used in pairs (a DX1 beingconnected to the trunk relay circuit and DX2 beingconnected to a single frequency signaling unit). Theymay be used in any combination, DX1 at one end of thecircuit and DX2 at the other, or with like units at eachend of the circuit. This equipment usually functionsover metallic circuits with loop resistance up to 5000ohms.

e. Pulse Link Repeater. The pulse-link repeater cir-cuit connects two signaling circuits, using E&M leads,by converting an incoming E-lead potential to an out-going M-lead potential in both directions of transmis-sion. This equipment does not connect to or affect thetalking it is connected in the signaling path only.

2-35. Vf and E&M Panels

A voice frequency jackfield is designed as an area inthe Technical Control Facility where voice frequencycircuits and their associated signal and control leadscan be patched, monitored and tested. A patch panel isa signal unit in the jackfield. There are four types ofvoice frequency patch panels in the TCF; the Equalbevel., the 4-wire, the 6-wire primary, and the 2-wireprimary patch panels. Each panel serves a differentfunction as described in paragraph 2-17.

a. Equal Level and 4-Wire Primary Patch Panels(fig. 2-15A) Each Equal Level and 4-wire primarypatch panel contains 12 channels. Each channel occu-pies a paired jackset (a jack& consists of 4 jacks ar-ranged vertically) of the panel as shown in figures2-15 and F0-2. The receive circuit occupies the leftjackset (odd numbered jacks) in each paired jackset,and the transmit circuit occupies the right jackset(even numbered jacks) of each paired jackset; there-fore, the jacks are alternately labeled REC andTRANS. The top row of jacks are labeled LINE and areelectrically toward the line or away from the Technical

patch panel has four cable connectors mounted on therear of the panel. As shown in figure F0-2, C1 and C3are used to bring the transmit and receive circuit leadsinto the panel. C2 and C4 are known as the normal-through connectors. The normal-through wiring whichconnects the line side to the equipment side of thepanel is routed through these connectors. Thusis provided to the normal-through connections for fu-ture uses, such as automation of the Technical ControlFacility.

b. 6-Wire Primary Voice Frequency Patch Panel(E&M Signaling). The 6-wire Primary Patch Panel is

panel between them. The E&M patch panel providessignaling jack appearances for the 12 channels above,as well as the 12 channels below it. A front view of anE&M signaling patch panel is shown in figure 2-15Band the interconnection diagram in figure 2-16. Theodd numbered jacks serve the E&M signaling leads ofthe vf above it while the even numbered jacks servethe E&M signaling leads of the vf panel below it. Thetop row of jacks is electrically toward the line, and thesecond row of jacks is toward the Technical ControlFacility equipment. As with other patch panels, thenormal&rough connections between the line andequipment sides of the panel (row 1 and row 2) arebrought out to a normal&rough connector for futureuse.

c. 2-Wire Primary Voice Frequency Patch Panel.This panel is similar to the 6-wire vf patch panel inthat it has four rows of jacks for line side, equipmentside, and monitoring operations. Since it is a 2-wirepanel, it can hold 24 channels. Refer to figure 2-17 forthe interconnection diagram of a 2-wire patch panel.

2-36 . Dc Pa t ch Pane l s

a. Primary Dc Patch Panel.(1) Panel Description (fig. 2-15). The primary dc

patch panel is that equipment within the Technicaloni-the

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A. VF PATCH PANEL

B. E & M (SIGNALING) PATCH PANEL

Figure 2-15. Voice frequency primary or equal level and signaling patch panels. front view

2-39

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Figure 2-16. E&M patch panel, interconnection diagram.

2 - 4 0

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Figure 2-17. Two-Wire voice frequency primary patch panel, interconnection diagram

2 - 4 1

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Figure 2-17. Two-Wire voice frequency primary patch panel, interconnection diagram

2 - 4 1

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Figure 2-18. Dc patch panel, low level receive, interconnection diagram.

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Figure 2-19. Dc patch panel, low level transmit, interconnection diagram.

2 - 4 4

radio communication links. The interconnection dia-gram of the receive panel is show in figure FO-4 andthe interconnection diagram of the transmit panel isshown in figure FO-5. It can be seen that the wiring issimilar to that previously discussed with the exceptionof the cut keys and lamps.

(2) Receive Panel Cut Keys Functioning (fig.FO-4). When the cut key is operated to the down posi-

tion, the indicator light is energized and the normal-through circuit is broken and terminated. The receivecircuit from the LINE side of the panel is terminatedthrough a 5.6K ohm loop resistor to ground. The tiplead of the circuit toward the Technical Control Facil-ity equipment is connected to hold battery. The corre-sponding ring lead is connected to an S lead and outputvia connector C1. This S lead provides a through pathfor any timing circuits which are present when the cutkey is operated. Contact No. 5 energizes the lamp andoutput -48 vdc through the L lead to connector C2.The L lead provides the capability of energizingremote lamp to indicate that the circuit is cut.

(3) Transmit Panel Cut Key Functioning (fig.FO-5). This cut key functions in a similar fashion asthat discussed (2) above, except the loop resistor isplaced in the cut circuit on the EQUIP side of thepatch panel and the hold battery is placed on the LINESide.

2 - 3 7 . M i s c e l l a n e o u s / I n t e r b a y P a t c h P a n -e l s and Trunking

a Miscellaneous Patch Panels (fig. 2-21). Miscella-neous (MISC) patch panels are located in the patch andtest bays to provide the flexibility required for testand monitoring operations. The jacks are wired andcross-connected as desired by TCF personnel. Figure2-21 provides a typical functional arrangement for amiscellaneous panel with 10 lamps in a Technical Con-trol Facility. Figure 2-27 provides the patch panelinterconnection diagram and block terminations. Thepatch panel provides such desirable jack arrangementsand functions as 600 ohm loads, parallel jacks, line re-versing (tip-to-ring, ring-to-tip), and -48 vdc power.The -48 vdc power is supplied via jacks 1 of rows 1and 2. These two jacks are engineered to avoid unsafeor undesired jacking of the -48 vdc by designing thejacks for use only with a special double pronged MISCDC patch cord. Jack 1, row 1 is an undersized jackwhich will accept only one prong of this patch cord.

b. Interbay Patch Panels. Each patch and test baycontains in interbay (INT) patch panel. Interbaytrunks are used to route circuits to other patch bays inthe Technical Control Facility. The various types ofinterbay trunks in the TCF are described below.

c. MISC/INT Patch Panels (fig. 2-22). These pads,located in dc patch and test bays, may be used to per-form either an interbay patch panel function or a mis-

TM 11-5895-1012-10

cellaneous patch panel function as described in a and babove respectively. The jacks contain normal-throughcontacts for greater flexibility as shown in figure2 - 2 2 .

d. Interbay Trunking Systems. The Technical Con-trol Facility-has a voice frequency trunking systemand a dc trunking system. The systems are designed toallow sufficient trunking of circuits from one patch ortest bay in the vf or dc area to any other bay in thatarea. The vf and dc interbay trunking systems are notinterconnected and come together only at the intermit-tent test stations.

(1) Voice Frequency Interbay Trunking System.The interbay trunking capability in the vf area is pro-vided by interbay patch panels which are mounted inthe bottom of every vf patch and test bay. The panelhas two rows of 24 jacks per row for a total of 48 inter-bay trunk appearances per bay. The front view of thepanel resembles that shown in figure 2-21, howeverthe interconnection diagram is that shown in figure2-23. Terminal blocks Cl and C2 of each panel arecabled to the vf cdf where the panels are cross-connect-ed to form a series interbay trunking system. Thecross-connecting is done in such a manner that thesame jack in each panel is assigned to the same patchor test bay. As an example, Jack 2, Bow 2, of everypanel provides a trunk to the same bay. This scheme isshown in figure 2-24A. TCF personnel can alter thepattern as desired to provide additional trunks be-tween heavy traffic bays or between bays and test sta-tions. This system provides, generally, only one trunkbetween any two voice frequency bays or test stations.However, the patch cord length usually allows the useof trunks on either side of the bay providing threetrunks to any one bay by direct trunking.

(2) DC Interbay Trunking System. Interbay trunk-ing capability in the dc area is provided by interbaypatch panels with 48 lamps mounted in the dc patchand test bays. The panel has two rows of 24 jacks andtwo rows of 24 in-use lamps, as shown in figure 2-25.The panel interconnection diagram is shown in figure2-26. The lamps are necessary since these cross panelsare interconnected at the dc cdf into a parallel config-uration (fig. 2-24B). Every pin on the block of oneinterbay panel with 48 lamps IS jumpered to the corre-sponding pin on the blocks of every second panel (oddpanels form a parallel configuration and even panelsform another parallel configuration). Each parallelconfiguration has 48 trunks for a total of 96 trunks inthe dc area. The configurations are referred to asparallel since an interbay trunk appears on the samejack of every second INT panel appearance. As an ex-ample, Jack 1, Row 1 of one panel is in parallel withJack 1, Row 1 of the INT panel two bays away and soon until all odd numbered and all even numbered baysare interconnected to form the two separate configura

2-45

TM 11-5895-1012-10

Figure 2-20. Dc Patch Panel (transmit or receive) with cut keys and lamps, front view.

2 - 4 6

TM 11-5895-1012-10

Figure 2-21. Typical miscellaneous patch panel, front view.

2 - 4 7

TM 11-5895-1012-10

Figure 2-22. MiscellaneousMiscellaneous/Interbay patch interconnection diagram.

2 - 4 8

TM 11-5895-1012-10

2 - 4 9Figure 2-23. Voice frequency interbay patch panel, interconnection diagram.

TM 11-5895-1012-10

2-50

Figure 2-24. Typical series and panel interbay trunking systems.

tions. When a trunk is put into use at one bay, thecorresponding in-use lamp will illuminate at all theinterbay panels where the trunk appears to indicatethe trunk is in use.

2-38. Voice Frequency and DC Test Equip-m e n t

A major responsibility of Technical Control Facilitypersonnel is that of monitoring and testing circuitsthrough the TCF to determine circuit quality and todetermine operating conditions. Additionally, they areresponsible for the rapid identification and isolation offaulty equipment in order to achieve optimum operat-ing effectiveness. Accordingly, assorted test and moni-tor equipment is located through the voice frequency

and dc Technical Control Facility areas to provide anefficient means for performing these operations. It isnot possible in a general type technical manual, suchas this, to list every specific piece of test equipment tonomenclature of manufacturers name that could befound on every TCF in the world. However, instead alisting by genre is provided. This listing will help youidentify the specific items installed at any TCF andbriefly describe its function.

a. Speaker Panels. Speaker panels are usuallymounted in the bottom of the voice frequency testbays. These panels are used for aural monitoring of vfcircuits carrying voice signals for the purpose of deter-mining continuity and/or the quality of the speechtraffic. The panel usually includes two amplifier

TM 11-5895-1012-10

Figure 2-25. Dc interbay patch panel with 48 lamps, front view.

2-51

TM 11-5895-1012-10

Figure 2-26. Dc interbay patch panel with 48 lamps, interconnection diagram.

speaker combinations. This allows two independent in-puts and outputs. Both inputs are usually wired tojacks in the miscellaneous patch panel of that particu-lar test bay. For monitoring purposes, either of thesetwo inputs may be patched via interbay trunks to themonitor (MON) jacks in the voice frequency patchpanel without degradation or interruption of circuitoperation.

b. Teat Bay Alarm Panels. Alarm panels are usuallymounted at the top of each voice frequency and dc cir-cuit test bay in the Technical Control Facility. Thepanel contains one or more rows of lights for the pur-pose of giving remote alarm indicates for selectedequipment alarm circuits. The alarms circuit to be re-moted are usually determined by the Technical Con-trol Facility personnel.

c. Noise Generator. The noise generator gives a flatresponse output signal over a wide range of the audio

spectrum. The output provides a signal to a circuitunder test for measure at the other end with a noisemeasuring test set.

d. Dual Channel Dc Amplifier Recorder. The dualchannel dc amplifier recorder is used for simultaneousreading of two related variables then the variablesneed to be analyzed with respect to each other in time,or when up to two variables need to be permanently re-corded.

e. Transmission Measuring Test Set. The transmis-sion measuring test set is used to measure transmis-sion line and system characteristics such as attenua-tion, frequency response, or gain. It contains a widerange oscillator, a voltmeter, and a patch panel tomatch both the oscillator and the voltmeter to thevarious impedances found on the DCS (usually 135,600 and 900 ohms).

f. Noise Measuring Test Set. The noise measuring

2-52

TM 11-5895-1012-10

Figure 2-27. Miscellaneous patch panel with 10 lamps, interconnection diagram.

2-53

TM 11-5895-1012-10

test set is used to measure signal levels, noise level andvolume units (VU). The test set usually has a number

filters for the inputs.Balance Test Set. The terminal balance

test set when provided* allows for connecting andswitching instruments required for each test withoutchanging patch cords to the circuits to be tested.

h. Wave Analyzer Test Set. The wave analyzer testset provides amplitude and frequency informationover a given band of frequencies. The test set canseparate frequency components of an input signal bymeans of selectable bandwidths and tuning controls.

i. Patter Generator. The pattern generator is usedto generate a wide variety of telegraph teat signal pat-terns having predetermined and controllable charac-teristics and parameters. The unit is used in conjunc-tion with data measuring equipment to test and evalu-ate the performance of data/TTY systems or equipment.

j. Singing Point Test Set. The singing point test setmeasures the singing margin of 4-wire transmissioncircuits using hybrid terminations by inserting a varia-ble, but known, gain into the circuit until oscillationoccurs. The test set may also be used as a variable gainamplifier with a maximum undistorted output ofusually 0 dBm at 600 ohms.

k. Impulse Noise Counter. The impulse noise count-er counts the number of impulses exceeding a numberof different selected levels for a selected length oftime. The unit provides a readout for each selected lev-el, each giving the number of times an impulse exceedsthe associated adjusted level.

l. Phase Jitter Measuring Set. The phase jittermeasuring set measures the peak to peak phase jitterindegrees.

m. Transmission Delaytransmission delay measuring testtransmitter and a receiver which is used to measuresignal delay and amplitude versus frequency.

n. Data Analysis. Data analysis test sets provide thecapability for comprehensive analysis and generation

data, start, stop data, and

nitor teleprinters areused to monitor teleprinter traffic in dc telegraphloops. A transmitting keyboard is usually includedwhich, in conjunction with one of the page printersand utilizing a spare dc circuit, may be used in com-municating between Technical Control Facilities for

the coordination of test fault isolation, or operationalactivities. Inputs to the monitor page printers areusually in the neutral mode. The output of the trans-mitting keyboard consists of dry contacts. The loopinto which this output is inserted requires the applica-tion of operating battery from an external source. Theprinters and keyboards may be used in circuit operat-ing at 60, 75, or 100 words per minute when appropri-ate speed change gears are used. A monitor teleprinterconverter panel is usually provided which will allowthe monitor teleprinter to be used without interupt-ing the circuit being tested. The converter permits theinsertion of the page printer into dc monitor jacks byconverting low level voltage variations into currentimpulses needed to drive the page printer.

p. Dual Meter Panels. The meter panel usually con-tains a high impedance voltmeter and low impedancemilliammeter. The milliammeter is used to measurethe telegraph loop current (high level). Loop current ismeasured by patching the meter input into a LINEMON or EQUIP MON jack at the equal level dc patchbays.

q. Low Led Meters. These meters, mounted overvarious dc patch bays, provide a low level voltage read-ing when patched into the monitor jack of a dc circuitvia the miscellaneous patch panel. The meters usuallyhave a zero center scale, with ± 15 vdc full deflection.

r. Reference Tone Generator. The referencegenerator provides 0, - 10, -8.7, and - 12.7 dBmtone levels (or others depending upon the manturer) to the patch and test bays. These test tone levelsmake jack appearances on the miscellaneous patchpanels and then distributed to each patch and test bay.

2-39. Digital Line Interface Unit (DLIU)

The digital line interface unit is a solid state plug-inprinted circuit module for use as a line isolator andlevel converter generally located between the primarydc and equal level dc patch bays. It accepts a highlevel, neutral or polar, or low level signal and convertsit to low level, polar and vice versa. The unit usually

te with either synchronous or start-stop dataup to 2400 baud. Automatic adjustable loop

current regulation for high level output lines is pro-vided as well as no transition/open loop detection andalarm, build-in loop battery fusing, and output moni-tor jack and self contained power supply for inter-cir-cuit operation.

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TM 11-5895-1012-10

C H A P T E R 3

E X A M P L E S O F O P E R A T I O N A L T C F ' S

Sec t ion I . P IRMASENS

3 - 1 . F u n c t i o n

a The Pirmasens TCF is a fixed station technicalcontrol facility containing equipment that providestermination, interconnection, patching, interfacing,conditioning, monitoring, and testing of voice fre-quency (vf) and direct current (dc) communications cir-cuits and signals.

b. The TCF performs the DCS Technical Controlmission for the supervision and control of the trans-mission media at the Pirmasens Radio Station. Thissite is a radio nodal point (fig. FO-6) in the EuropeanWideband Communication system (EWCS) servingmicrowave links to Langerkopf (LKF), Zweibrucken(ZBN), and Donnersberg (DON). In addition, the siteprovides cable links to local vf and dc subscribers.

3-2. Technical Characteristics

equipment are listed below. Detailed technical charac-teristics of the individual components that are in-cluded in the TCF are listed in the appropriate tech-nical manual.

a VF Patching Facilities.Equal Level Jack Appearances (Full duplex)

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1800 ea6/Wire Primary (cable) Jack Appearances . 96 ea4/Wire Primary (Cable) Jack Appearances (Full

duplex) . . . . . . . . . . . . . . . . . . . . . . . . . . 720 ea2/Wire Primary (Cable) Jack Appearances (In

Bays 1.16, 1.17, 1.18)‘. . . . . . . . . . . . . .720 eaNominal Signal Level.. . . . . . . . . . . . . . . .0 dbmNominal Impedance . . . . . . . . . . . . . . . 600 ohms

b. VF Conditioning and Interface Equipment.. . . . . . . . . ..<......... 1320 ea

l . . . . . . . . . . . . 200 ea. . . . . . . . . . . . . . 40 ea

3-3. Description of the TCF

25 Hz Ringing Supply.. . . . .. . . . . . . . . . . .1 setSignal Supply Unit (2600 Hz) . . . . . . . . . . . . leaSignal Supply Unit (1600 Hz) . . . . c.. . . . .. leaSingle Frequency Signaling-2600 Hz. . . . .75 eaSingle Frequency Signaling Unit-16 Hz

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82 ead. DC Patching Facilities.

DC (Equal Level) Jack Appearances (Full duplex).. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 864 ea

DC W/Cut Key (Equal Level) Jack Appearances(Full duplex) . . . . . . . . . . . . . . . . . . . . . .144 ea

Dc Primary (Cable) Jack Appearances (Full du-plex . . . . . . . . . . . . . . . . . . . . . . . . . . . . 480 ea

e. DC Line Conditioning Equipment.Digital Line Interface Units (Full Duplex Shelf

Space). . . . . . . . . . . . . . . . . . . . . . . . . .540 eaf. Orderwire Capability.

Voice Orderwire Circuits.. . . . . . . . . . . . .20 eaDc Orderwire Terminals . . . . . . . . . . . . . . . 24 eaAC Power Requirements. 208/120 VAC and

380/220 VAC at 50 Hz.A. DC Power Supplies.

-48 VDC . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 ea-24 VDC . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 ea+130 VDC . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 ea-60 VDC . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 ea+60 VDC . . . . . . . . . . . . . . . . . . . . . . . . . . 2 ea±6 VDC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 ea

in a common building with multi-plex voice frequency carrier telegraph (VFCT) equip-ment, and microwave equipment at the Pirmasensradio station, Germany. The TCF is housed in severalrooms as shown in figure FO-8. The site is situated inthree major areas; the dc and primary vf patch or testfacility (Room 9), the vf equal level patch and testfacilities (Room 12), and the line conditioning facilities(Room 8).

a Description of Equipment w No. 1. Row 1 con-tains vf and dc patch and ties as well as thealarm and fuse bays for the

3 - 1

TM 11-5895-1012-10

tain dc patch panels (low level). Mounted above each dcpatch panel is a Weston 273 low level voltmeter formonitoring purposes. Each patch bay contains aninterbay panel with lamps and a MISC/INT patchpanel. Bays 1.4 and 1.5 are dc test bays. Bay 1.4 con-tains an alarm panel, Digital Data AnalysisAN/GGM-11, Express Link Order Wire UnitTA-923/FSC, and an AN/FGC-80 teletypewriter. Bay1.5 also contains an alarm panel, an intercom unit,Digital Data Analysis AN/GGM-15, and a voice order-wire (O/W) unit. Bay 1.5 contains an interbay and aMISC/INT panel similar to the patch bays.

(2) Primary VF Patch and Test Facilities. Bay1.15 contains 6-wire primary vf patch panels; bays1.16, 1.17, and 1.18 contain 2-wire primary vf patchpanels. Bay 1.18 also contains four Hub Data Repeat-ers. At the bottom of each patch panel is an INT paneland MISC panel with 10 lamps. Bays 1.13 and 1.14 aretest bays. Each test bay contains an alarm panel, andINT panel, and a MISC panel with 10 lamps. Test bay1.14 contains a TTS-26BDR test set, a TTS-27 termi-nal balance switching set, and a TTS-56RP noise gen-erator. Bay 1.13 also contains Express Link OrderWire Unit TA-923/FSC, a dc meter panel and DataANALYSIS Central DAC-5.

(3) Alarm, Circuit Breaker, Orderwire, and BlankBays. Bays 1.19 and 1.20 contain orderwire equip-ment. Bay 1.21 contains the TCF’s alarm equipment.This consists of two major/minor alarm panels, twomajor alarm panels, and an alarm converter. Bay 1.22contains dc circuit breaker panels. The top panel in thebay is the -24VDC breaker panel for supplying thealarm system. The bottom five panels supply -48VDC power to the patch and test facilities. Bay 1.23 isblank for future expansion.

b. Description of Equipment Row No. 2. Row no. 2contains dc and primary vf patch and test facilities, asdoes row no. 1. Bays 2.1 through 218 containAN/UGC-61X DC O/W terminals. Bays 2.9 through2.15 contain dc patch and test facilities, while bays2.16 through 2.23 contain primary vf patch and testfacilities.

(1) DC Patch and Test Facilities. Bays 2.9, 2.10,2.13, 2.14, and 2.15 contain dc patch facilities (lowlevel). Each patch bay has a low level voltmeter mount-ed above it and has an INT panel, a, MISC panel and awriting shelf mounted below the jackfields. Bays 2.14and 2.15 are equipped with cut keys and lamps for usein conjunction with high frequency radio circuits.Bays 2.11 and 2.12 are dc test bays. Each test bay con-tains an alarm panel and a writing shelf. Bay 2.11 con-tains the voice O/W panel, an INT panel with lamps,and a MISC/INT panel. Bay 2.12 contains the intercomunit In addition the two test bays contain the follow-ing test equipment, Model PG-303A pattern genera-tor, Teletype Carrier Test Set TCTS-2A, Digital Data

Analysis AN/GGM-15, and an AN/FGC-80 teletypewriter set.

(2) 4-Wire Primary VF Patch and Test Facilities.Bays 2.16 through 2.18 and 2.21 through 2.23 contain4-wire primary vf patch facilities. Each patch bay con-tains an INT panel and a MISC panel with 10 lamps.Bays 2.19 and 2.20 are vf test bays. Each test bay con-tains an alarm panel, and INT panel, a MISC panelwith 10 lamps, and a writing shelf. Bay 2.19 contains avoice O/W panel and a speaker panel. Mounted abovebay 2.19 is a remote intercom speaker. Bay 2.20 con-tains a TA-923/FSC orderwire unit and a monitorspeaker panel. In addition the two vf test bays containthe following teat equipments, TTS-12AR singingpoint test set, a TTS-37BR noise measuring set, aTTS-27R terminal balance switching set, anAN/USM-181B test set, and a TTS-56R noise genera-tor.

c. Description of Equipment Row No. 1A. Row 1Acontains spare bays, HF radio control bays, and vfequal level (EL) patch and test facilities.

(1) Radio Control Bays. Bays 1A.3 and 1A.4 eachcontain a test bay alarm panel. Bay 1A.3 contains twoSCC recorder announcers and three AN/FTA-28 tele-phone terminals. Bay 1A.4 contains C-7667/FRR re-ceiver control, a C7669/FRT transmitter control, aTA-923/FSC order wire unit and a TT-98/FG tele-typewriter set. Bays 1A.5, 1A.6, and 1A.7 are used forHF radio control. The three bays contain Litcom Model699A and Model 699B receiver and transmitter con-trol units.

(2) Equal Level VF Patch and Test Facilities.Bays 1A.8, 1A.9, 1A.12, 1A.13, and 1A.14 contain ELpatch facilities. Below the jackfield in each patch bayis located an INT panel and a MISC panel with 10lamps and a writing shelf. In addition, bay 1A.10 con-tains a voice O/W unit, a dual speaker panel. Mountedabove bay 1A.10 is a remote intercom speaker. ATA-923/FSC order wire unit is mounted in bay 1A.11.The two vf test bays contain the following test equipments, speaker panels, a TTS-37BR noise measuringset, an AN/USM-181B test set, a 1450-TBR attenu-ator panel, and a R561B oscilloscope with storagerack for extra modules.

d. Description of Equipment Row No. 2A. Row 2Acontains vf equal level patch bay and test bay has anINT panel and a MISC panel with 10 lamps mounted atthe bottom of the bay. There are two sets of test baysin row 2A, test bays 2A.3, 2A.4 and test bays 2A.10,2A.11. The left bay in each set of test bays (bays 2A.4and 2A.11) contains a voice O/W panel and speakerpanel. The right bays in each set (bays 2A.3 and 2A.10)contain an intercom unit and rack for stowing modulesfor the oscilloscope. Bay 2A.3 contains a TA-923/FSCorder wire unit. All four test bays contain alarm panelsand writing shelves. In addition, bays 2A.10 and

3 - 2

TM 11-5895-1012-10

2A.11 contain a TTS-37BR noiseadditional monitor speaker panels, aoscilloscope and an AN/USM-181B test set.

e. Description of the VF CDF Row No. 3. The VFCDF is constructed of open metal framework. One sideof the frame, known as the horizontal side, contains 10

rows of 56 horizontally oriented terminal blocks. Theother side of the frame, know as the vertical side,contains 10 rows of 56 blocks oriented vertically. Incolumns 22 through 26 of the vertical side, the termi-nal blocks are replaced by cable protectors for the pur-pose of terminating outside cable.

f. Description of Equipment Row No. 4. Bay 4.1through 4.15 and 4.19 are the voice frequency univer-sal conditioning equipment bays. Each bay containsten shelves with each shelf capable of containing 12modules of vf line conditioning equipment. A fuse andalarm panel is mounted above the shelves with anintermediate distribution frame (IDF) located at thetop of each bay for the purpose of easy cross-connect-ing. Bay 4.20 is known as the vf nonuniversal condi-tioning equipment bay. Mounted in the bay from topto bottom is a -48VDC containing equipmentbreaker panel, two shelves of Stelma 4-Way/4-Wirebridges, two Stelma SSU-1, signal supply units, a bal-last lamp panel, a ring alarm and monitor panel, two25 Hz ring generators, and six shelves of NorthernRadio type 1030, model 2, 4-Way/4-Wire bridges.

g. Description of Equipment Row No. 5. Row No. 5contains all the dc condition equipment (DLIU's) neces-sary for the operation of the site. In addition, the 1000Hz test tone generators are located in Row 5.

(1) DLIU Bays. Bays 5.1 through 5.9 contain thedigital line interface unit-s (DLIU). Each bay contains10 shelves, each shelf capable of containing sixDLIU's. A fuse/alarm panel is mounted above theshelves with an IDF at the top of each bay.

(2) Tone Source Bays. Bays 5.19 and 5.20 containthe 1000 Hz tune sources for the TCF. A TTS-39A-4tone generator is mounted at the top of each bay. Eachbay also contains 14 TTS-39D-4 distribution ampli-fier panels.

h. Description of DC CDF Row No. 6. The DC CDFis constructed of Open metal framework. The vertical-ly oriented terminal blocks occupy a matrix of 10 rowsof 48 blocks per row. In columns 41, 42, and 43, theblocks are replaced with cable protectors for the pur-pose of terminating outside cable.

i. Description of Miscellaneous Equipment.(1) Supervisor's Console. Located at the head of all

and test facility rows is the supervisor’s con-in the console is a voice O/W panel and an

unit. An Order Wire IntercommunicationsSection II. BERLIN

3 - 4 . F u n c t i o n

TCF is a fixed station Technical Con-

Termination Unit TA-930(V)/FSC is on the console.Behind the console is an AN/FGC-25XDC O/W termi-nal and test station no 1.

(2) Intermediate Test Stations. The intermediatetest station provides the capability of performing QAtests from locations remote to the patch and test facil-ities. Each test bay contains three interbay panels, oneMISC function panel, an intercom speaker panel, andavailable rackspace for test equipment. Test stationNo. 2 contains a HP-302A wave analyzer.

(3) Mobile Test Bays No. 1, 2, and 3 (not located).The TCF has three mobile test bays. The bays provide

for the mounting of test equipment. Eachtest bay contains a MISC function panel and a writingshelf. Mobile test bay No. 1 contains a speaker panel,intercom unit, a Computer Measurements CompanyNo. 800A, 802A, and 831B an AN/USM-181B testset, and an envelope delay distortion measuring set(ACTION LAB INC). Mobile test bay No. 2 contains aTektronix R561B and extra module rack, an HP-320dual channel dc amplifier recorder, and an ACTON462A transmission delay measuring set. Mobile testbay No. 3 contains a speaker panel, a TTS-58AR im-pulse noise counter, an HP-312A frequency selectivevoltmeter, an HP-3550 transmission measuring set,and an envelope delay distortion measuring setTS-2669/GCM.

(4) AC Power Panels. The ac power panels supply=ing the TCF are located at the head of rows no. 1 and 2.The fuse panels on the left supply 220 VAC power toceiling lights, wall outlets, and ventilator exhaustfans. The TCF technical equipment is supplied by thetwo tech power panels which are fed via a 100A,208/120 VAC fuse panel. The non-technical loads aresupplied via the non-technical power panel which isfed via the 63A, 208/120 VAC fuse panel.

(5) DC Distribution Bays 6.1 through 6.5. The dcpower hays supply +130, ±60, -48, -24, and±6VDC to the TCF. Bay 6.1 contains the control paneland two rectifiers used to supply +130VDC. Bay 6.2contains the two PS alarm panels for the ±60VDC sys-tem. Below these panels are two +60 VDC and two- 60VDC power supplies, ± 60 VDC distribution fusepanels, a spare fuse panel, ±6VDC fuse panels and the±6VDC power supplies. Located in bay 6.3 are two-24VDC Solar power supplies, a Lorain power boardmonitor panel (-24VDC) and a -24VDC fuse panelLocated in bay 6.4 are two -48VDC power supplies,each with a -48VDC meter panel mounted above it.Bay 6.5 contains all the -48VDC distribution equip-ment which includes a ground bar, a -48VDC PS

Lorain power board monitorfuse distribution panels.

trol Facility containing equipment that provides term-ination, inter-connection, patching, interfacing, condi

3-3

TM 11-5895-1012-10

tioning, monitoring, and testing of voice frequencyand direct current communications circuits and sig-nals.

b. The TCF performs the Defense CommunicationsSystem (DCS) Technical Control mission for the super-vision and control of the transmission media at theBerlin Radio Station. This site is a radio nodal point‘(fig. FO-8) in the European Wideband CommunicationSystem (EWCS) serving a microwave link to Tempel-hof (TPF) and a French and British link. A tropospher-ic link to Bocksburg (BBG) and a satellite link to Land-stuhl (LDL). In addition, the site providers cable linksto local vf and dc subscribers.

3 - 5 .

The technical characteristics of the TCF and relatedequipment are listed below. Detailed technical charac-teristics of the individual components that are in-cluded in the TCF are listed in the appropriate tech-nical manuals.

a. VF Patching Facilities.Equal Level Jack Appearances (2 wire) . . .864 eaPrimary Jack Appearances (2 wire) . . . . . . 960 eaNominal Signal Leave (E.L. Patch Bays) . . 0 dbmNominal Impedance.. . . . . . . . . . . . . . 600 ohms

b. VF Conditioning and Interface Equipment.

C.

d.

e.

Echo Suppressor. . . . . . . . . . . ...:. . . . . . 36 eaStrappable Pads. . . . . . . . . . . . . . . . . . . . . .72 ea4W Term Set . . . . . . . . . . . . . . . . . . . . . . . .31 eaAmplitude Equalizer . . . . . . . . . . . . . . . . . .56 eaLine Amplifier . . . . . . . . . . . . . . . . . . . . . .218 ea4 Way - 4W Bridge . . . . . . . . . . . . . . . . . . . .2 ea6 Way - 4W Bridge . . . . . . . . . . . . . . . . . . . . .2 eaEnvelope Delay Equalizer . . . . . . . . . . . . . .12 eaSignal Conditioning Equipment Quantities.Test Tone Sources . . . . . . . . . . . . . . . . . . . .20 eaRingdown Converter E&M to 25Hz/dc to 25 Hz

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60 eaPulse Link Repeater. . . . . . . . . . . . . . . . ..100 ea25 Hz Ringing Supply. . . . . . . . . . . . . . . . . . 1 setSignal Supply Unit (2600 Hz) . . . . . . . . . . . .2 eaSignal Supply Unit (1600 Hz) . . . . . . . . . . . .2 eaSingle Freq. Signal Unit-2600 Hz . . . . . .108 eaSingle Freq. Signaling Unit-1600 Hz. . . . . 10 eaOrderwire Capability.Voice Orderwire Units . . . . . . . . . . . . . . . . . .6 eaDTMF Access Units . . . . . . . . . . . . . . . . . . . .3 eaDc Orderwire Terminals . . . . . . . . . . . . . . . .6 eaDC Patching Facilities.Dc Low Level Jack Appearances (Full

Duplex) . . . . . . . . . . . . . . . . . . . . . . . . . .120 eaDC High Level Jack Appearances (Full

Duplex) . . . . . . . . . . . . . . . . . . . . . . . . . . . 72 eaDc Lane Conditioning Equipment.Digital Line Interface Unite (Full Duplex). .95 eaAC Power Requirements. 108/120 vac, three

phase, at 50 Hz.h. Dc Power Supplies.

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 ea+120vdc . . . . . . . . . . . . . . . . . . . . . . . . . . . .2 ea±60vdc . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 ea±6vdc . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 ea

3-6. Descript ion of the TCF(Fig. FO-9)

a The TCF is housed in a building connected to theBerlin Tropo/Microwave Site. Four rooms are withinthe building, air conditioning plant room, office, main-tenance room, and the technical control room.

b. The technical control room has four bay areas.(1) Operation area, consisting of rows 1 and 2

along with the supervisor’s console and AN/UGC-54teletypewriter.

(2) Conditioning and interface area, which is row3.

(3) Combined Distribution Frame (CDF).(4) Voice frequency circuit telegraph and power

bays in row 5.c. The technical control and maintenance rooms are

illuminated by rows of ceiling mounted fluorescentlamps. Emergency lights (battery powered) are mount-ed on the right wall as you enter the building. The acinput power distribution panel along with the tech-nical and non-technical power distribution panels aremounted on the opposite wall.

mainte-nance rooms raised and consists of a metal frame

d. The floor in the technical control and

supporting tile covered wooden squares. All cablingand wiring between bays, CDF and ground box arebelow the raised floor.

e. A description of the supervisor’s console is as fol-lows:

(1) The supervisor's console is located at the endsof equipment rows 1 and 2, and in front of the DCA,reporting orderwire teletypewriter. This allows easyaccess to all dc orderwire machines. (One at the end ofeach equipment row).

(2) The console consists of two cabinets with awriting shelf between the cabinets. The left band cab-inet contains storage drawers, ac power outlets at thebottom, and a power monitor panel at the top. Thepower monitor panel contains an ac voltmeter, fre-quency meter, and a dc voltmeter.

Row 1 contains the following equipment:

wire audio patch panels. Bay 1.02 has the No. 1 Uni-versal Transmission Measuring System (UTMS) re-mote digital display unit at the top. Plus Signaling

3 - 4

TM 11-5895-1012-10

Test Set TTS-26BDR is mounted in the bay below thedisplay unit. Bay 1.02 also contains six 2-wire audio

patch panels and a speaker panel. Bay 1.04 is the cabletest bay, containing the No. 2 UTMS remote digitaldisplay, a HP-180 AR/TDR , a HP-4800vector impedance meter, a speaker panel, and vf order-wire equipment. Bay 1.06 has the No. 3 UTMS remotedigital display at the top. This bay also contains six 2-wire audio patch pan&and a speaker panel. Bay 1.07contains four 2-wire audio patch panels and aSB-1642 top resistance panel. The portion above thewriting shelf of bay 1.08 is blank for future use as re-quired. There is a SB-1642 loop resistance panel belowthe writing shelf.

(2) High Level DC Patch Bays 1.09 and 1.10. Eachof these bays contain a 48 lamp interbay panel, MISCpanel, writing shelf, a loop resistance panel, and haveac power outlets at the bottom. Bay 1.09 also containsa dc meter panel and four dc patch panels. In additionBay 1.10 contains a digital multimeter, two dc patchpanels and Telegraph Test Set AN/GGM-15(V).

(3) Fuse and Alarm Bay 1.11 and Orderwire Bay1.12. Ray contains two major/minor alarm panels, amajor alarm panel, three SB-1523/FT fuse panels,three loop resistance panels, and ac outlets at the bot-tom of the bay. Bay 1.12 is an AN/UGC-61X dc order-wire teletypewriter set.

g. Row 2 contains the following equipment:(1) Equal Level Patch Bays 2.01 Through 2.06.

Each equal level patch bay contains space for eight 2-wire audio patch panels, INT panel, MISC panel, writ-ing shelf, and a dual ac power outlet. Bays 2.02 and2.06 have only six audio patch panels installed. Bay2.04 is blank above and below the INT panel, MISCpanel, and writing shelf. Bays 2.02 and 2.05 each havea remote digital display at the top of the bay and adual speaker panel below the writing shelves.

(2) Quality Assurance Bays 2.07, 2.08 and 2.09.These three bays each contain an INT panel, MISCpanel, writing shelf, and dual ac power outlets. A base-band monitor panel and two echo suppressor controlpanels are mounted near the center of bay 2.07. TheTTI-1140 Universal Transmission Measuring System(UTMS) master unit and power supply, along with theNo. 7 remote digital display are mounted in bay 2.08.The UTMS associated relay panel, and a dual speakerpanel are in the bottom of bay 2.09. The remainingspace in the bays is provided for mounting testequipment. The test equipment may be rearranged orreplaced as required by test requirements or change inthe state of the art.

(3) Low Level DC Patch Bays 2.10 and 2.11. Eachpatch bay has a low level voltmeter mounted above itand has a 48 lamp INT panel, a MISC panel and writ-ing shelf mounted below the jackfields. Bay 2.10 con-tains five transmit patch panels and bay 2.11 contains

five receive patch panels.(4) Low Level Test Bay 2.12 and DC Orderwire

Bay 2.13. Test bay 2.12 is shown with a digitalmultimeter and AN/GGM-15(V) Telegraph Test Setinstalled. (These equipments may be changed as re-quired). Below the test equipment area there is a 48lamp INT panel, MISC panel, and a writing shelf. Thelow level ±6 volt power supplies, fuse panels andalarm panel are in the bay below the writing shelf. Bay2.13 is an AN/UGC-61X dc orderwire teletypewriterset.

h. Row 3 contains the following equipment:(1) Universal conditioning Equipment Bays. All

the bays in row 3 except bay 3.04, 3.08 and 3.09 areuniversal conditioning equipment bays. Intermediatedistribution frames (IDF) are mounted at the top ofthese bays. Below the IDF's are fuse-alarm panels.Each bay contains ten universal conditioning equipment shelves, each shelf containing 12 module slots.Conditioning equipment modules are inserted into theshelves as required to build circuits through the tech-nical control facility.

(2) DLIU Bays. Bays 3.08 and 3.09 contain thedigital line interface units (DLIU). Each bay contains10 shelves, each shelf capable of containing sixDLIU’s. A fuse/alarm panel is mounted above theshelves with an IDF at the top of each bay.

(3) Non-Universal Bay 3.04. At the top of the baythere is a UTMS remote digital display, a MISC paneland a 4-way-4-wire bridge shelf. A 25 Hz ringing supply system consisting of ballast lamp panel, 20 Hzalarm and monitor panel, and two 25 Hz ring genera-tors are mounted in the center of the bay. At the bot-tom of the bay there is a station reference tone source(TTS-39A) and four distribution amplifier panels(TTS-39D).

i. The combined distribution frame (CDF) in row 4is constructed of open metal framework. One side ofthe frame, known as the horizontal side, contains 30rows of 10 horizontal terminal blocks. The other sideof the frame, known as the vertical side, contains 31columns of 9 vertical blocks per column. The firstseven columns contain 750 four wire, line protectorblocks.

j. Row 5 contains the following equipment:(1) Mobile Test Buy 5.01. This bay is mounted on

dolly type wheels to allow it to be moved throughoutthe TCF as required. The bay contains a INT/MISCpanel, a storage drawer, and an ac power connector.The mobile bay provides rack space for the mountingof such test equipment as a digital multimeter, trans-mission measuring set, envelope delay test set and X-Yrecorder.

(2) Voice Frequency Carrier Telegraph Bays 5.02Through 5.05. Each of the four voice frequency carriertelegraph (VFCT) bays is a Telegraph Terminal

3-5

TM 11-5895-1012-10

(3) Mux. Bay 5.06 and Power Equipment Bays5.07 and 5.08. Bay 5.06 is a Collins MTX-201, VFCT.Bay 5.07 is the -48 vdc power source bay. There aretwo -48 power supplies at the bottom of the bay. Fusedistribution panels along with a Lorain power hoardmonitor panel are above the power supplies. Bay 5.08houses the ±60 vdc and 120 vdc power equipment

370-1 power supplies are below the Hub repeater. Twopower supplies strapped for + and - 60 vdc out-puts.

(4) Orderwire Equipment Bay 5.09. The Dual-Tone Multiple Frequency (DTMF) orderwire equipmeat bay contains an SD-3751/FSC fuse panel, Re-mote Link orderwire Unit TA-924/FSC, one line cardshelf, and two common equipment shelves. Duplex acpower outlets are in the front and rear bottom of thebay. IDF blocks, inductors, and a component board arein the rear of the bay.

along with a modified SB-1642 loop resistance panel.A Hub repeater is also mounted in the bay. Two dcvoltmeter panels, three fuse panels and an alarm panelare at the top of the bay. Four Northern Radio Model

Section III . PENTAGON

3 - 7 . F u n c t i o n

a. Pentagon Telecommunications Center (fig.FO-10). The U.S. Army Communications Command

Telecommunications Center (PTC)mmunications Systems (DCS) for

b. Technical Control Facility (fig. FO-11). Thecal Control Facility (TCF) at the Penta-technical control over BED and BLACK-ITAL, and VIDEO circuits appearing atse are comprised of military-owned VFCT

s and leased DC and data circuits. The highdata circuits are in the 2400 to 50K BAUDThe low speed circuits are predominantly

secure circuits. Test and maintenance is also providedon Government-owned lines and circuits.

c. Patch and Test Facility. (fig. FO-12). The P & Tfunction includes the monitoring of circuits and equip.ment within a station, as well as the selection andapplication of the station facilities and associatedequipment, as n to keep the station’s operatingand standby communications links and circuits at peak

. The Technical Controller coordinatesin communications services at the station,alternate routings, directs the correction of

functions, restores service when outages occur,and coordinates link and station tests. The P & T Facil-

e station encompasses these areas whichwith jacks, and test instruments to pro-

vide access to the circuits for the purpose of perform-monitor, patch and test operations.

To efficiently perform the technical control func-

tions required to keep all communication links at theirpeak operating condition, all personnel must be thor-oughly familiar with the station capabilities and thefunctions of all equipment in the station. In addition,familiarization with circuit links of related technicalcontrol is required.

e. The Pentagon technical control facility is themain Army TCF serving the Washington D.C. area.The facility provides many high priority circuits toand from various local government users to locationsscattered throughout the free world and to the Krem-lin. Users and connecting sites often change.

f. The patch and test facilities of the TCF provideaccess to each circuit for monitoring, rerouting, andtesting. Access is provided to both the black (en-crypted) and the red (clear) sides of the circuits.

3-8 . Techn ica l Charac te r i s t i c s

a.

b.

C.

d.

e.

VF Patching Facilities:Red VF Jack Appearances (2-wire). . . . . .264 eaBlack VF Jack Appearances (2-wire) . . . .960 eaNominal Test Tone Signal Leval . . . . . . -2 dbmNominal Circuit Impedance . . . . . . . .600 ohmsNormal Send Signal Leval . . . . . . . . . . . +8 dbmNormal Receive Signal Leval . . . . . . . . -13 dbm

DC Patching Facilities:Red DC Jack Sets.. . . . . . . . . . . . . . . . . .912 eaBlack DC Jack Sets . . . . . . . . . . . . . . . . 1,296 eaNominal Signal Level . . . . . . . . . . . . . . . ±6 vdc

Video Patching FacilitiesRed Video Jack Appearances.. . . . . . . . .160 eaBlack Video Jack Appearances . . . . . . . . 100 eaNominal Circuit Impedance . . . . . . . . .75 ohms

AC Power Requirements . . . . . . . . . . . . . . . . . . .208/120 vac, 3 phase, 60 HZ.

DC Power Supplies6 VDC . . . . . . . . . . . . . . . . . 4 ea: 2 Red, 2 Black24 VDC. . . . . . . . . . . . . . . . . 4 ea: 2 Red, 2 Black48 VDC . . . . . . . . . . . . . . . . 4 ea: 2 Red, 2 Black

3-9. Description of the TCF

The equipment is housed in two different rooms. All of

3 - 6

TM 11-5895-1012-10

the facilities (except the quality assurance (QA) equip-ment) are located in TCF, room 5A910 (fig. FO-12).There are three bays of QA equipment in the Electron-ic Maintenance Room (para 3-10). As shown in figureFO-12, the TCF consists of two rows of equipmentbays, a red cable vault, and red and black ground andpower distribution boxes. In addition the room con-tains Crypto equipment, modems, voice frequency car-rier telegraph (VFCT) equipment and etc. Equipmentrows No. 1 and No. 2 are described in paragraphs a andb below. Sample bay elevations are shown in figures3-1, 3-2, and 3-3.

a. Description of Equipment Row No. 1(1) General. Equipment row No. 1 contains 21

bays of patch and test equipment and four bays ofDCL/MOLINK equipment. Bays 1.22 through 1.24(DCL/MOLINK) are covered in (C) PDEP11-5895-832-14(2). Row No. 1 is called the blackequipment row, because bays 1.1 through 1.21 connectto unsecure or encrypted circuits.

(2) Black VF and Digital IDF Bays. Bay 1.1 con-&b of two intermediate distribution frame (IDF)bays. Bay 1.10 consists of three IDF bays. Each baycontains a front door to allow access to a patch cordtype cross connect matrix. The IDF's are similar anddiscussed in paragraph 3-11.

(3) Black VF Patch Bays. Bays 1.2, 1.3, 1.4, 1.6and 1.7 are the VF patch bays. Each of these bays con-tains eight 2-wire audio patch panels and an interbay(INT) patch panel. Bay 2.1 has a R-390 radio receiverin the bay below the patch panels. Bays 1.3 and 1.7each have a 60 station voice order wire panel, that arefurnished and maintained by the telephone company.Bays 1.4 and 1.6 have dual speaker panels andAM-911/FG audio frequency amplifiers mountedbelow the patch panels.

(4) Black VF Test Bay 1.5. This bay contains vari-ous test equipment. There is a writing shelf with a mis-cellaneous (MISC) and INT panel above the shelf. Inaddition there are two test equipment connectionpanels. Test equipment without rear test lead con-nectors are connected to the MISC panel through thetest equipment connection panels.

(5) Video Monitor and Station Clock Bays 1.8 and1.9. Bay 1.8 has two video monitors at the top, used tomonitor the TCF door and outside hall. A panel with apush-button switch for unlocking the door is below themonitors. There are five TWINAX wide band patchpanels in the bay. The remainder of the bay is used tomount test equipment. Bay 1.9 is a TDS-2 StationClock Bay.

(6) Black Digital Patch Bays. Bays 1.11, 1.12,1.13, 1.15, 1.16, 1.17, 1.19, 1.20 and 1.21 are the

black digital patch bays. Each bay has a ± 15 vdcmeter mounted in the panel at the top. There are sixuniversal dc patch panels and a INT panel with 48

lamps in each bay. The bottom of bay 1.11 mounts theblack -48 vdc power system; consisting of two 48 vdcpower supplies, an alarm panel, and a fused power dis-tribution panel. Bays 1.12 and 1.19 each contain anorder-wire panel. Bays 1.13 and 1.15 have writingshelves with AN/FGG-80 t&typewriter sets mountedon the shelves. One 24 vdc power supply is in bay 1.16with a second unit in bay 1.17. Bay 1.16 contains the24 vdc meter panel, alarm panel and fused power dis-tribution panel. Bay 1.17 also contains the black 6 vdcpower system; consisting of two power supplies (withalarms), meter panel, and fused power distributionpanel. Bay 1.21 includes the black indicating equipment; consisting of a MAJOR/MINOR alarm panel,audible alarm panel and two crypto ancillary unit/corn-mon control unit (CAU/CCU) alarm panels.

(7) Black Digital Test Bays. Bays 1.14 and 1.18are the black digital test bays. The bays are similar inconfiguration. Each bay contains a ± 150 vdc meterpanel, a 601 Data Transmission Test Set, HP-180BROscilloscope with connection panel, AN/GGM-15(V)Telegraph Test Set, INT panel with 48 lamps, and awriting shelf.

b. Description of Equipment Row No. 2(1) General. Equipment row No. 2 contains 20

bays of equipment and four bays of IDF patch cordcross connect matrixes. The four IDF bays are allnumbered 2.21. Row No. 2 is called the red equipmentrow, because the circuits may carry secure informationin clear test. Bays 2.1 through 2.20 are described in (2)through (6) below.

(2) Special Intelligence Bay 2.1. SI bay 2.1 isisolated from the rest of the TCF. The bay contains acolor video monitor at the top with eight videodistribution amplifiers, and three 75 ohm patchpanels. Between the monitor and amplifiers there aretwo universal dc patch panels (digital patch panels)and three 2-wire audio patch panels (VF patch panels).The bay also has its own IDF consisting of two rows ofpatch cord cross connect matrixes.

(3) Red Digital Patch Bays (fig. 3-1). The reddigital patch bays are bay 2.3 through 2.6, 2.8 through2.11 and 2.13 through 2.16. Each of these bays has a± 15 vdc meter mounted in a panel at the top of thebay. Below the meter panel there are six digital patchpanels and a INT panel with 48 lamps. Bays 2.11, 2.13and 2.14 each contain a writing shelf used to mountAN/FGC-80 teletypewriter sets. Each bay has blankpanels below the patch panel. The blank panels may beremoved to allow installation of equipment as re-quired.

(4) Red Digital Test Bays (fig. 3-2). Bays 2.2, 2.7and 2.12 are the red digital test bays. Each of thesetest bays is used to mount test and monitor equipment.In addition there is an INT panel with 48 lamps and awriting shelf in each bay.

3 - 7

TM 11-5895-1012-10

(5) Red Power and Video Monitor Bays. Bay 2.17mounts six dc power supplies (two 48 volt, two 24 voltand two 6 volt), along with associated fused distribu-tion panels and alarm panels. The 6 vdc and 24 vdcsupplies do not contain current and volt meters. There

Figure 3-1. Red digital patch bay (typical), front view.

fore, a meter panel is provided to measure the outputof these supplies. At the top of this bay there is aMAJOR/MINOR alarm panel along with an associatedaudible alarm panel. Video monitor bay 2.18 has a

Figure 3-2. Red digital test bay (typical), front view.

3 - 8

TM 11-5895-1012-10

3-10. Description of Quality AssuranceT e s t C e n t e r

(fig. 3-4)

The QA test center consists of three bays located in theElectronic maintenance room. The bays contain testequipment and panels as shown in figure 3-4. The testcenter is connected to red circuits in the TCF throughthe RED REIAX 75 ohm INT TRUNK in bay 2. BlackTCF circuits are connected to the QA test centerthrough the black INT panel in bay 1.3.

3-11. Intermediate Distribution

a. General. There are four IDF's in the TCF areaThey are an integral part of the Technical Control Fa-cility and each equipment signaling input and outputconnections are terminated at an IDF. In addition, theinput and output signals of each patch panel and cir-cuit line are also terminated at an IDF. (Wide hand cir-cuits are not connected through IDF's).

b. Description. Each IDF consists of a matrix madeup of rows of cross-connect panels. A panel containsten jack type patch modules (A through H, and J, andK). Each module has six multi-colored rows of 26 jacks.The color of the jack rows at the front of the modules,from left to right are: red (A), white (B), blue (C), yel-low (D), black (E), and orange (F). Each of the 156 jacksis connected to a pin on one of three associated connec-tors mounted on the rear of the panel. The first 48jacks on the module are connected to pins 1 through 48on connector J1. Module jacks 40 through 96 are con-nected to pine 1 through 48 on connector J2. Modulejacks 97 through 144 are connected to pins 1 through48 on connector J3. Module jacks 145 through 156 arealso connected to connector J1, J2 and J3. Four jacksto each connector. The connectors are cabled to patch

3-12. Digital Circuits, General

TCF provides cross-connection. monitoring, testing,circuit patching access, and timing clock for black andred digital circuits. A typical black circuit is discussedin paragraph 3-13. All digital circuits are connectedthrough a Universal Digital Patch Panel. The patchpanel and its different configurations are discussed in

paragraphs 3-14 and 3-15.Figure 3-3. Red vf test bay (typical), front view.

3 - 9

TM 11-5895-1012-10

EL3Z0084Figure 3-4. Quality assurance test center

3 - 1 0

TM 11-5895-1012-10

3-13 . Typ ica l Digital Circuit(fig. FO-13)

a. General. In this example of a black digital circuit,the Universal Digital Patch Panel jack sets are pro-grammed with a group 4 module in the send circuitand a group 5 module in the receive circuit. Refer toparagraph 3-156 and c for patch panel circuit details.This circuit is cross-connected in IDF bay 1.10. The lo-cal equipment (EQUIP side of circuit) is cabled to mod-ule A of panel 6. The line equipment (LINE side of cir-cuit) is cabled to module A of panel 1. The jack sets ofthe Universal Digital Patch Panel are cabled to moduleA of panel 2. Optional devices are not used, but con-nections that could be used are shown.

b. Send Circuit. To complete the send circuit, dual-plug, cross-connect patch cords are installed as fol-lows:

(1) Patch cord No. 4, from jacks 1 and 2, moduleA, panel 6 to jacks 1 and 2, row 2, module A, panel 2.This connects the transmit data output of the userequipment to pin 5 of patch panel connector C-l. Thisis the jack sets tip (T1) lead, which is normal-throughwired to pin 1 (tipT) of patch panel connector C-l. Pin1 of C-1 is cabled to jack 1 of row 1 in module A, panel2. The transmit data return is also cross-connectedwith patch cord No. 4, and is connected to a commontie point.

(2) Patch cord No. 1, between jacks 1 and 2, row 1,module A, panel 2 and pins 1 and 2, row 1, module A,panel 1 completea the transmit data and transmit datareturn to the line equipment.

(3) Patch cord No. 5, from jacks 3 and 4, row 1,module A, panel 6 to jacks 3 and 4, row 2, module A,panel 2 connects the transmit clock through the R1and R leads of the patch panel jack set, to jacks 3 and4. row 1. module A. panel 2 of the IDF. The transmitclock return is also connected to the common tie pointthrough patch cord No. 5.

(4) Patch cord No. 2, from jacks 3 and 4, row 1,module A, panel 2 to jacks 3 and 4, row 1, module A,panel 1 completes the transmit clock and transmitclock return to the line equipment.

c. Receive Circuit. To complete the receive circuit,dual cross-connect patch cords are installed as follows:

(1) Patch cord No. 7, from jacks 1 and 2, row 2,module A, panel 1 to jacks 1 and 2, row 3, module A,panel 2 connects the receive data line to the tip (T) lead

set. The T lead is nor-1 lead of the patch pan-row 4, module A, panelrd connects the receive

patch panel jack set to the receive pair of the userequipment.

(3) Patch cord No. 8, from jacks 3 and 4, row 2,module A, panel 1 to jacks 3 and 4, row 3, module A,panel 2 connects the receive clock to the ring (R) leadof the patch panel jack set. The R lead is normal-through wired to the R1 lead of the jack set and cabledto jack 3, row 4, module A, panel 2 of the IDF. Thesame patch cord also connects the receive clock returnto a common tie point and to jack 4, row 4, module A,panel 2 of the IDF.

(4) Patch curd No. 11, from jacks 3 and 4, row 4,module A, panel 2 to jacks 3 and 4, row 2, module A,panel 6 completes the receive clock circuit to the localequipment.

d. Red Digital Circuit. A red digital circuit is con-nected in a similar manner and will not be discussed.

3-14. Universal Digital

a. Description. The fronttains 24 sets of four jacks with a switch and lamp thatis associated with each jack set. There are three rowsof identification (ID) card holders. The card holders al-low the circuit and equipment connected to the circuitto easily be identified. The rear of each patch panel hastwo connectors (Cl and C2), that are used to connectthe jack set circuits (through connectors J1 and J2) tothe IDF. Below the connectors are 24 program mod-ules. Between the connectors and program boardsthere is a jack set ID strip indicating the jack set asso-ciated with each program board.

b. Circuit Functions (fig. FO-15). Each jack set isconnected (through a flexible printed circuit board) toa program board. The board is programmed by a pro-gram module (containing jumpers) to set up an opera-tional circuit. The functions that may be performed bythe circuits are given in (1) through (6) below. Two typ-ical circuits for which modules are available are dis-cussed in paragraph 3-15.

(1) Provides a normal through path for digital sig-nals when no patches are made.

(2) When patching in a replacement sending de-vice, the patching configuration will terminate the in-terrupted sending equipment in an impedance equal tothe input impedance of the receiving device.

(3) When patching in a replacement receiving de-vice the patching configuration will hold the interrupted receiving equipment with a holding voltage or cur-rent equal to the mark voltage or current transmittedby the sending device.

(4) The patch panel will perform the above func-tions for all the following types of digital signals:

(a) Low level ± 6VDC send and receive.(b) Low level ± 3VDC send and receive.(c) High level polar or neutral send and receive.(d) Low level receive with associated timing.

3-11

TM 11-5895-1012-10

send with timing from an externalstandard to both sending and receiving devices.

(5) The patch panel also incorporates a specialfunction for circuits utilizing either an externaltiming standard or timing from a receiving device to asending device. When a transmitted signal is to bepatched back receiving portion of the sameequipment for purposes, a problem would nor-mally arise. Since external timing is necessarily intro-duced on the line side of a jack field, a line-send-to-line-

l (back to back) patch required to performve test for equipment external to the TCF con-

two timing signals (one injected into the sendfield and one received on the incoming line). Con-versely, an equipment send-to-equipment-receive (backto back equip) patch required to perform the test forequipment internal to the TCF contains no timing sig-nal. When timing is sent from a receiving device to a

the same problem can occur (i.e., twoon a back to hack line and none on auip).

A push button "back-to-back” switch allows the remov-al of one of the two timing signals present in a back to

line patch and the introduction of timing in ato-back equip patch. An indicator light as well as

switch position indicates the activation of this func-tion in all cases.

(6) The signal common “ring” lead of an interrupt-ed signal is never left open. It may be supplied DCground or another program elected termination.

M3 to M2D3 to E2M3 to J3H3 to E1L1 to J1F2 to F3H3 to N3 (Not shown)Al to H1 (Not shown)A2 to M1 (Not shownE3 to K1 (Not shown)H3 to N3 (Not shown)C3 to D1 (Not shown)C3 to K3 (Not shown)

(2) When a patch cord plug is inserted into theLINE jack, the following connections are made.

TerminalT

T1R1 External timing

(3) When a patch cord plug is inserted into theEQUIP jack, the following connections are made.

TerminalT

3-15. Universal Digital Patch Panel,P r o g r a m s

R External timingT1 To plugged line equipmentR1 To plugged line equipment

c. Black Receive Circuit, Program Module GP-5(fig. FO-16).

(1) This programming module connects the fol-lowing terminals:

B2 to E1B1 to J3C1 to F3B3 to J1C2 to N2D2 to K3

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TerminationTo TCF equipmentTo TCF equipmentUnterminatedUnterminated

Terminal TerminationT UnterminatedR UnterminatedT1 From pl line equipmentR1 From pl line equipment

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C H A P T E R 4

T E C H N I C A L C O N T R O L F A C I L I T I E S O P E R A T I O N S

Section I. OPERATION PRACTICES AND METHODS

4 - 1 . S y s t e m M a n a g e m e n t

sions. Examples of its specific station operationalfunctions are:

(1) In the case of the Berlin TCF, to provide arelay service to Templehof (TPF) and be the centralaccess point to the Defense Communications Systemfor subscribers in the local area.

(2) In the case of Pirmasens, to provide widebandrelay service to Zweibruken (ZBN), Langerkopf (LKF),and Donnersberg (DON) as well as being the centralaccess point to the DCS.

b. The mission of a TCF encompassed all of theseactions necessary to maintain flexibility in traffic andcircuit routing, reliability of through and terminatingcircuits, and peak efficiency in transmission quality.This capability can be realized only by employing ap-proved management principles and by strict adherenceto proven standard operating procedures at all sta-tions.

c. Overall system management direction resideswith the Defense Communications Agency (DCA) andthe Army Communications Command (ACC). Specific

designed as the station control center and is equippedto permit effective station management. All operation-al orders, circuit activation and deactivation func-tions, system reporting, alternate routing procedures,

formed by the Technical Control operators. Much ofthe content of this chapter is therefore addressedspecifically to the station Technical Controllers and isintended to be used as a working guide in conjunctionwith station SOP's, records, and individual equipmentmanuals and handbooks. Since the circuit configura-tion is subject to operational changes a detailed studyof the equipment description of those items on siteshould be made to ensure familiarity with the facilitiesprovided. Moat of the day-to-day Technical Control op-erations require a thorough understanding of the com-plete station facility andthe Technical Controllering knowledge of the

4 - 3 . S t a t i o n M a n a g e m e n t F a c i l i t i e s a n dU s a g e

4 - 2 . S t a t i o n M a n a g e m e n t A p p r o a c h .(1) High Frequency Interface. The multiplexed

4 - 1

T M 1 1 - 5 8 9 5 - 1 0 1 2 - 1 0

the TCF. Rerouting of the multiplexed groups is readi-ly accomplished at this central point by patching.

(2) Voice Frequency Channel Interface. The multi-plex channel modems are wired to the Equal LevelPatch bays in the VF Technical Control area. Thepatching facilities in this area provide access to the cir-cuits.

(3) DC Circuit Interface. In the TCF DC area,patching access is provided to DC subscriber loops andVFCT circuits by the DC patch facilities.

b. Monitoring and Testing Functions.(1) Monitor and Test Point Interface. All VF and

DC jacksets include a monitor jack appearance. Thesejacks are arranged to permit monitoring and testingwithout interrupting the circuit.

(2) Teat Bay Interface. The test bays containtransmission measuring equipment and other testitem to facilitate maintenance, fault isolation, analy-sis, and correction.

4 - 5 . O r d e r w i r e

c. Status Reporting and Coordination Functions.Operating personnel at the station are the primaryusers of the supervisory Subsystem which providesorderwire communications. This subsystem providescommunications with other stations as required. Re-porting requirements are established by the stationSOP.

4-4. Duties r

a. General. The principal functions of the Technicalcontroller are to moni d patch, as required,

Effective control of thatcomes under the responsiFacility requires format

4 - 6 . O r d e r w i r e P r o c e d u r e s

4 - 2

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location. Technical control notices will contain a fullheduled TELECON’s with the details

arrangements with ade-circuit, conduct tests and

request is received withoutadvance notice, the contacted TCF will provide theservice as rapidly as possible.

d. If the user reports trouble, immediate action willbe taken to clear the trouble or provide an alternatecircuit within normal restoration priorities.

e. When notified by the user that the TELECON isfinished, the controller will initiate action to breakdown the special arrangements used and return thecircuit to normal use.

4-9 . On-Ca l l Pa t ches

On-call patches is in no way intended to substitute forplanning to meet known communications require-ments. They will be activated for a period not toexceed 72 hours. If the requirement is to exceed 72hours, the requesting activity will be advised to submitan emergency minor telecommunications requirement.When a request for an on-call patch is received the fol-lowing action will be taken by the technical controller

4-7 . Orde rwi re C i rcu i t D i sc ip l ine

a. Determine and establish the route to be employedand the equipment required to provide satisfactoryservice.

b. When the on-call patch cannot be established,contact the appropriate DOCC for assistance inaccordance with established procedures.

c. Report all on-call patches in accordance withestablished procedures.

d. Construct a temporary CCSD in accordance withestablished procedures.

e. Deactivate the on-call patch when notified by theuser that it is no longer required. The technical con-troller will coordinate with the next TCF throughwhich the circuit is patched to effect deactivation. AllTFC's will follow the same procedure until the circuitis restored to normal. When the user will not releasean on-cdl patch after 72 hours and an emergency tele-communication request has not been received, theappropriate DOCC will be notified for permission tobreak down the circuit.4-8. TELECON Circuits4 - 1 0 . S c h e d u l e d S e r v i c e I n t e r r u p t i o n s

Policy requires that the best possible communicationsservice be provided to users of the DCS commensuratewith available equipment and facilities. To providethis service it may be necessary, at times, to removeequipment from service or, in cases of major engineer-ing changes, require the complete shutdown of a com-munications facility. These outages, which will be held

4 - 3

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to a minimum, are known in advance and every effortmust be made to provide continuing service during thetime a facility is out of service. When it is absolutelynecessary to remove communications equipment, facil-ities, or an entire DCS Station from service, the plan-ning, notification, and restoral of service must bethorough and complete.

a. Planning. Service interruption will normally bescheduled when minimum communications impactwill occur and will provide, where possible, for unin-terrupted service to users. Planned actions will betime-phased to allow control to be maintained at alltime, to ensure that communications capabilities willnot be exceeded and to ensure the communications aresuccessfully completed. Planning will include recoveryshould an emergency arise which would prevent thecompletion of planned actions. In addition, the plan-ning will consider leasing of additional circuits fromcommercial carriers, as necessary, to provide uninter-rupted service.

4 - 1 1 . E m e r g e n c y I n t e r r u p t i o n o f S e r v i c e

b. Notification. It is of utmost importance that allusers of the DCS be informed of any action that will ormay tend to degrade their service.

c. Supervision. Control and implementation of ascheduled service interruption rests with the TCF.Supervising DOCC elements will ensure that depend-able communications are maintained to the elementimplementing the outage.

4-12. Interruption of Service to CorrectH a z a r d o u s C o n d i t i o n s

d. No User Service Interruption.(1) When there will be no interruption of user

service and sufficient spare or backup equipment isavailable during the affected period, no additional re-sponsibilities, other than normal control practices, arerequired.

(2) When there will be no interruption of userservice and sufficient spare or backup equipment isnot available during the affected period, the DCS sta-tion will notify the appropriate DOCC and operationand maintenance element of this hazardous condition.If necessary, the DOCC element may cancel or requestrescheduling of this type of interruption. Further, itmay be required that the users be notified of the exist-ing hazardous condition.

e. Interruption of User Service. For service interuption, other than a complete DCS Station,ordination and approval is not required on

prior

releases of single circuits or single channelconcurrence has been obtained fromterminals. However, if the interrupmagnitude, but less than the complenation and approval must be accomptained in accordance with existing reguladirectives. Where the complete DCS Statvolved coordination and approval isance with existing regulations and directives eventhough user concurrence has been obtained.

prior coordination. However, as soon as possible, thecircumstances involved will be reported to the variouselements in accordance with existing regulations anddirectives.

cation is waived for complete station interruption ofshort duration to correct hazardous conditions provid-ing all the following conditions are satisfied:

a The station is in a hazardous condition and thecondition has been reported in accordance with exist-ing regulations and directives.

b. All necessary equipment and the technical extise is available on-site to correct the hazardous cotion.

c. User concurrence for the outage has been ob-tained.

d. The interruption is scheduled for non-busy hours.e. Reroute or restoral actions will not be requiredf. Appropriate DOCC elements have been contac

and advised that the above requirements have beenmet prior to the time of interruption occurs.

Section II. CIRCUIT REROUTING

4-13. Introduction 4-14. Normal Circuit Rerouting

Circuit rerouting is normally accomplished on aplanned (scheduled) basis on orders from DCA or ACC.

All normal circuit rerouting requirements are deter-

System planning and growth, circuit priorities, link ormined by ACC or higher authority and are primarilybased on satisfying customer demands or

equipments reliability, subscriber population density,improving

communication services in a particular area of the sys-party line or command net configurations, and systemmaintenance may be major system operating factorswhich generate circuit rerouting requirements. In ad-dition, system or equipment failures may necessitateemergency circuit rerouting.

4-4

tern. In the latter casement is the result ofoperating and servicetaken from the daily technical control and mainte-nance logs and reports which are submitted by all

ACC and/or higher headquarters.

pleted, and the circuit verified in service, the stationrecords are updated and details promptly forwarded toACC in order that the system master files and recordscan be maintains current at all times.

4-15. Circuit

Any circuit rerouting necessitated by system, equipment, or facilities failure can be identified as an emer-gency requirement. Emergency circuit rerouting is ac-complished in so far as possible, by temporary cord,plug and jack patching arrangement? at or through theTechnical Control Facility using installed spare equipments or channels to bypass the failed equipment orportion of the circuit or system. The magnitude of fail-ure will determine the degree of emergency attachedto each service interruption. A majority of the servicetroubles encountered can be attributed to failure of aminor item of in-station equipment; in this case, the

station personnel are able to restore service expedi-tiously by patching in spare equipment or components.As soon as maintenance personnel repair or replace thefailed items, the circuit is restored to its normal path.All troubles must be logged and reported, but the useof installed spares need not be coordinated with ACC

TM 11-5895-1012-10

prior to getting the circuits back into service. Any non-patching type rerouting actions required to restoreservice to less than highest priority critical circuitsmust be first coordinated with or have the approval ofDCA or ACC.

4-16. Catastrophic Failure

The failure of link equipment, transmitters, or multi-channel equipment involving critical highest prioritycircuits, either by error or intent of man, or by naturalforces, are considered catastrophic failures. Underthese conditions, the restoration of service to criticaland high priority circuits is of paramount importance.Of equal importance at this time is the need to notifyACC of the failure event, the point of failure, extent ofdamage, estimate of work, equipment, and time in-volved in correcting the failure, and what has beendone or is being done to restore service. Station super-visors and station Technical Controllers immediatelytake action to reroute predetermined critical and highpriority circuits to the maximum degree possible overavailable spares whenever alternate routing links areavailable. As services are restored, DCA and ACC arenotified. DCA or ACC evaluates initial reports and allsubsequent status reports and initiates necessary in-structions to Station Supervisors and Technical Con-trollers detailing additional circuits to be rerouted androutes to be used. DCA or ACC also indicates which, ifany, lesser priority circuits will be preempted in orderto maintain a maximum service balance throughoutthe entire system until the failures can be completelyrestored to normal service.

Section III. PATCHING OPERATIONS

4-17. Pu of Patching

Patching is defined as the rearrangement of the elec-trical interconnections among items of station equipment by means of pat&cords and jackfields.

a. Service Restoration. The various patching facili-ties provided in the station Technical Control area en-able the Technical Controller to take positive action torestore service when a circuit failure has been localizedto a station. Such restoration action consists of bypass-ing the defective equipment and substituting likeequipment from the complement of operational sparesand, similarly, substituting spare, or lower priority,channels for those degraded or inoperative. The substi-tution of equipment usually involves only a localpatching operation, while substitution of channels re-quires a coordinated patching operation at the distantterminal.

b. Fault Isolation by Substitution. Substitution ofstation equipment and channels by patching opera-

a valuable fault isolation technique. A logicalre of successive substitutions of equipment

and/or channels usually locates the trouble. Often, it ispossible to patch out all station equipment in onepatching operation, establishing quickly whether thefault is in any of the local station’s equipment. Once achannel or equipment has been patched out, test equipment is employed to evaluate circuit performance andto localize the trouble.

c. Service Continuity During Maintenance. Pre-ventive maintenance routines require periodic qualitycontrol tests (Section VI) and adjustments of channelsand station equipment. When it is necessary to con-duct such tests on assigned channels or equipment,,service is maintained by a patching substitution. Faultisolation (Section IV) requires that the defective equipment is disconnected from the circuit and a spare substituted. This substitution is accomplished by patch-ing.

d. Operational Spares. Operational spares facilitiesconsist of spare multiplex and VFCT channels andselected items of equipment cross-connected intospecific spare configurations. Whenever such spare

4 - 5

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equipment is available, spare circuits, which corre-spond to the DCS options in use at the station, may beestablished to permit rapid restoration of circuits byin-station patching.

4-18. Patching Precautions

a. Temporary Measure. The use of patchcords to setup or rearrange circuits is intended as a strictly tem-porary measure. Service restoration patches should betaken down as soon as the fault condition has been cleared. In some cases, circuit orders may be issuedwhich specify that patchcords be used to set up or rear-range a circuit to fill an emergency or temporary re-quirement. Such orders may specify, for instance, thatcircuits be established without delay by patching, andlater by cross-connected at the frame to make a per-manent configuration. The patch is to be taken downas soon as the normal circuit is arranged. The opera-tional objective is to keep the jackfields as free ofpatchcords as possible. A multiplicity of patches in ajackfield frequently results in confusion as to the pur-pose and authority of the patches, and whether theyare still required. To preclude such confusion, identifi-cation tags should be attached to any pat&cord setupwhich is to be left in place at the end of a TechnicalControllers duty shift. The identification tag shouldcontain the following minimum information: circuitnumber, terminal locations, using agency, mode ofoperation, authority, and time to be taken down.

b. Patching Technique and Sequence. When patch-ing operational circuits, it is essential that interrup-tion, or service outage resulting from the actual patch-ing procedure, be kept to an absolute minimum dura-tion. In most patching operations, it is possible to limitthe effect on a VP circuit to a momentary click, and ona TTY circuit to a few garbled characters. This mini-mum effect can be realized, however, only when theTechnical Controller selects and follows the correct se-quence in inserting the plugs in the jacks. The order inwhich this is done is important. Each of the many pos-sible patching operations must be considered individu-ally to determine the optimum order of events in thepatching procedure. Experienced Technical Con-trollers always take a moment to think out the wholepatching procedure before plugging into the jacksets.In general, the spare or alternate signal path shouldbe set up first. The plugs should then be loosely set inthe proper NORMAL-THROUGH jacksets, located inthe signal path of the circuit to be transferred. Finally,in a coordinated procedure, the plugs should be simul-taneously pushed all the way into the NORMALTHROUGH jacksets at two locations that constitutethe end of the substitution path.

4-19. Reporting Patching Operations

Patching operations which result in reconfiguration of

channels, rerouting of circuits, or cause interruption ofservice must generally be reported to higher headquar-ters. The specific reporting procedures to be followedare contained in the current station SOP.

a Equipment Substitution. No operations reportsare required for the substitution of equipment duringroutine maintenance operations. A Failure Reportmust be completed, however, if an equipment failurehas occurred.

b. HF Patching. Except as authorized in the currentSOP, group patches may not be performed in themultiplex ares without prior coordination with, andapproval of, the DCA and ACC. Notice must be fur-nished to the DCA and ACC following completion ofthe HF patching operation.

c. Channel Substitution. The DCA sad ACC must beinformed when a circuit is transferred to a spare chan-nel, or to a channel of lower priority circuit. The noticeshould specify the time, circuit number, channel desig-nator, reason, and expected duration of the rearrange-ment. This report is normally submitted after-the-fact,since the Technical Controller must take immediateaction when patching is required to restore service.When it is necessary to preempt a lower priority cir-cuit to obtain a substitution channel, the using agencymust also be informed. When the circuit is restored,the using agency and higher headquarters must benotified.

4-20. Patching Operations Conduthe VF Pa tch ing Fac i l i t i e s

a. General. The jackfields associated with the VFpatching facilities are used to gain access to signals invoice-frequency (300 to 3400 Hz) circuits for monitor-ing purposes, and to perform circuit rerouting, testmeasurements, level adjustments, and restoration ofservice by equipment substitution. Representativepatching operations are given in b, c, and d below. Thepatch panels and jacks used are discussed in Chapter 2.The patching operations are shown in figures 4-1through 4-3.

NOTEThe patching operations described below donot take into consideration the extension ofE&M signalling leads through a patch panel.Where there is a signalling lead extension,use additional patch cords to transfer over allportions of the circuit.

b. Transfer of a Circuit to a Spare MultiplexChannel (fig. 4-1). The situation requires, for test ormaintenance purposes, that the user assigned tochannel 5, be transferred to channel 2. This patch ismade at the equal level patch panel (fig. 2-15) and theprocedure is the same for Station A and Station B.

(1) Place two patch cord plugs loosely into channel2 REC LINE and TRANS LINE jacks.

4 - 6

(2) Place the plugs on the other end of the patchcords loosely into the channel 5 REC EQU and TRANSEQU jacks.

(3) Establish voice contact between the TechnicalControllers at Station A and Station B.

(4) One Technical Controller will take charge andon a prearranged signal, usually the count-of-three, allloose plugs are set into the jacks simultaneously.

(5) The transmit aide of the patched off channel(in this case channel 5) is terminated with a 600-ohmtermination plug set into the TRANS LINE jack.

c. Transfer of an Active (Circuit to a Spare CablePair (fig. 4-2). The situation requires that for test ormaintenance purposes, the active circuit or channel 5be transferred to the tail segment cable pair for sparechannel 2. This patch is made at the primary patchpanel (fig. 2-15) at Station A and the Patch and TestFacility patch panel at the other end of the cable. Thepatching operations are the same at both ends of thecable. Only the patching operation at the TCF is cov-ered below.

(1) Place two patch cord plugs loosely into thechannel 2 REC LINE and TRANS LINE jacks.

(2) Place the plugs on the other end of the patchcords loosely into the channel 1 REC EQU and TRANSEQU jacks respectively.

(3) Establish voice contact between the TCF andthe PTF.

(4) The Technical Controller will take charge andon a prearranged signal, usually the count-of-three, allloose plugs are set into the jacks simultaneously.

d. Substitution of Line Conditioning Equipment(fig. 4-3). The situation requires that for test or main-tenance purposes, the spare line conditioning equip=ment (channel 2) be substituted for the active line con-ditioning equipment (channel 5). Before the patch ismade, check the spare channel line conditioning equipment to make sure it is configured the same as theactive channel. The patching is accomplished at theprimary and equal level patch panels (fig. 2-15) at Sta-tion A. Since the patch panels are normally physicallyseparated, two Technical Controllers are needed toperform the operation with minimum interference tothe users. The procedure described below is the sameat both patch panels.

(1) At the equal level patch panel, place two patchcord plugs loosely into channel 5 REC LINE andTRANS LINE jacks. Place the plugs on the other endof the patch cords loosely into the channel 2 REC EQUand TRANS EQU jacks respectively.

(2) At the primary patch panel, place two patchcord plugs loosely into the channel 2 REC EQU andTRANS EQU jacks. Place the plugs on the other end ofthe patch cords loosely into the channel 5 REC LINEand TRANS LINE jacks respectively.

(3) Establish voice contact between the two patch

TM 11-5895-1012-10

panels. On the count-of-three, all loose plugs are setinto the jacks simultaneously.

(4) On the equal level patch panel, terminate thechannel TRANS LINE with a 600-ohm terminationplug set into the TRANS LINE jack.

4-21. Patching Operations at Dc PatchingFacilities

a. General. The jackfields in the Dc patch bays areemployed to gain access to Dc circuits for monitoringpurposes and to perform circuit rerouting, testmeasurements and restoration of service by equipmentsubstitution. Representative patching operations aregiven in b, c, and d below. A cut-key is provided tointerrupt a telegraph channel for tactical considera-tions, or for the correction of an operational faultcondition at either the subscriber station locations. Inthe event a condition exists which caused the teletype-writer equipment at the locations to run open,the Technical Controller activates the appropriate cut-keys to isolate the subscriber loops affected and ap-plies hold battery to the subscriber teletypewritermachines. Upon correction of the condition, the cut-keys are restored to normal position. When a cut-key isactivated, the following actions occur: the telegraphcircuit is interrupted, hold battery is applied to thechannel terminating unit and the associated cut lampindicator is activated. This cut-key is also employed forscheduled interruptions of circuits such as those en-countered with high frequency radio systems.

b. Transfer of a Dc Circuit to a Spare VFCT Channel(fig. 4-4). The situation requires that for test or main-tenance purposes, a teletypewriter circuit is to betransferred from VFCT channel 1 to a spare or lowerpriority channel 2. The patching operation isaccomplished at the equal level dc patch panel at boththe local and distant station. Coordination is requiredso that the patch is made simultaneously at both endsof the communications path to preclude loss of largeblocks of record traffic.

(1) Place two patch cord plugs loosely into thechannel 2 REC LINE and TRANS LINE jacks.

(2) Place the plugs on the other end of the patchcord loosely into channel 1 REC EQU and TRANSEQU jacks respectively.

(3) Establish voice contact with the distant sta-tion. One Technical Controller will take charge and ona prearranged signal, usually the count-of-three, allloose plugs are set into the jacks simultaneously (atboth ends of the circuit).

c. Transfer of a Dc Circuit to a Spare Digital LineInterface Unit (DLIU) (fig. 4-5). The situation requiresthat for test or maintenance purposes, a teletypewritercircuit is to be transferred from the DLIU associatedwith channel 1, the normal channel, to the spare chan-nel 2 DLIU. Before the transfer can be made the spare

4-7

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Figure 4-1. Transfer of circuit to spare multiplex channel at the equal level patch panel.

4 - 8

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Figure 4-2. Transfer of current to spare cable circuit at the primary patch panel.

4-9

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Figure 4-3. Substitution of line conditioning equipment using the equal level and primary patch panels.

4 -10

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Figure 4-4. Transfer of a Dc circuit to a spare VFCT channel.

4 - 1 1

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patching is accomplished at both the equal level dc andprimary dc patch panels. Since the patch panels are transferred to the tail segment cable pair for sparenormally physically separated, two Technical Con- channel 2. This patch is made at the primary dc patchtrollers are needed to perform the operation with panel (fig. 2-15) and the Patch and Test Facility, orminimum interference to the user. The procedure similar patching facility, at the other end of the cable.described below it the same at both patch panels. The patching operations are the same at both ends of

(1) At the primary dc patch panel, place two patch the cable. Only the patching operation at the TCF iscord plugs loosely into channel 1 REC LINE and covered below.TRANS LINE jacks. Place the plugs on the other end (1) Place two patch cord plugs loosely into theof the patch cores loosely into channel 2 REC EQU and channel 2 REC LINE and TRANS LINE jacksTRANS EQU jacks respectively. (2) Place the plugs on the other end of the patch

(2) At the equal level dc patch panel place the cords loosely into the channel 1 REC EQU and TRANSpatch cord plugs loosely into the channel 1 REC LINE and EQU jacks respectively.TRANS LINE jacks. Place the plugs on the other end (3) Establish voice contact between the TCF andof the cords loosely into channel 2 REC EQU and PTF.TRANS EQU jacks respectively. (4) The Technical Controller will take charge, and

(3) Establish voice contact between the two patch on a prearranged signal, usually the count-of-three, allpanels. On the count-of-three, all loose plugs are set loose plugs are set into the jacks simultaneously.into the jacks simultaneously.

Section IV. FAILURES AND FAULT ISOLATION

4-22. General

a. All transmission media with breakout capabilityentering a DCS Station appears on the jack fields inthe Technical Control Facility for control and restoral

b. The Technical Controllers are responsible for alltransmission media entering, terminating or transit-ing a DCS Station.

(1) All traffic will be stopped where practicablebefore any action is taken that will interrupt its flow.When actions can be predicted; e.g. scheduled main-tenance, the user will be notified in advance in orderthat traffic may be stopped at the scheduled time.

(2) Occasionally, traffic will be interrupted dueto unforeseen events, such as transmission mediadegradation or equipment failure, Traffic may also beinterrupted by preemption of the circuit to restore ahigher priority user. In all such cases, the user will benotified of the transmission media failure or preemp-tion to permit them to stop traffic and maintain con-tinuity.

4 - 2 3 . C i r c u i t O u t a g e s

The Technical Controller is responsible for identifica-tion of all outages or interruptions on the circuit. Tech-nical Controllers are also responsible for restoration ofservice with minimum loss of operating time. Con-trollers will test, monitor, and observe outgoing andincoming circuits and channels to ensure proper opera-tion. They will coordinate with distant stations andlocal users, as necessary to isolate the report troubles.

4-12

All service interruptions must be logged, regardless ofperiod of outage.

4-24. fault Isolation

Fault isolation is the process of determining the loca-tion of a trouble within a circuit, or within the trans-mission media which carries the circuit The troublecould be in any of the transmitting facilities of one sta-tion, the receiving facilities of the adjacent station, themedia connecting them, or the user's equipment whichterminates the circuit. After the general area of atrouble has been isolated; e.g. media, user equipment,access lines, etc., a decision can be made to provide thequickest method of restoral. Fault isolation is not afinger-pointing or blame-fixing exercise. The basicpurpose is to locate the source of a trouble and get itfixed, regardless of where it is, or which piece of equipment is at fault. The same problem recurring at fre-quent intervals is of prime concern to both DCA andthe operation and maintenance agency, and correctivemeasures must be taken. However, this is a by-product, not the purpose of fault isolation.

a. The first step in fault isolation is the recognitionthat a problem exists. On the surface, fault recognitionmay seem to be a trite statement. However, the major-ity of problems are the result of someone failing torecognize that trouble signs are appearing. Troublerecognition may be a result of quality control testing,equipment sensors and alarms, customer complaint, orany combination of these. The main point is that whenthe trouble signs appear, regardless of how or from

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Figure 4-5 Transfer of a DC circuit to a spare digital line interface unit (DLIU).

4-13

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Figure 4-6. Transfer of a circuit to a spare cable pair.

4-14

a system such as the DCS, there is little room for error.Even the smallest error can easily be compounded intoa series of errors which can render a circuit, group, sys-tem, or service completely unuseable. Every stationand link in the system was originally tested and ac-cepted as meeting a specified level of performance. Inorder to continue operating at that level, each andevery one of the electrical standards must be main-tained with the established parameters.

c. The DCS is made up of many different types ofequipment which perform identical functions, but donot necessarily have the same electrical character-istics. For example, not all of the voice frequency chan-nel multiplex equipments in the DCS are designed fora - 16 dBm test tone level input to the voice frequencymodulator. Because of the detail differences whichexist, there are no cut and dried, test-point by test-point fault isolation procedures which cover all pos-sible installations. There are certain functional areaswhich are the same in all systems, regardless of the in-stalled equipment The procedures given in this sec-tion are addressed to functional areas rather than spe-cific signal and test tone levels at the various equipments. In addition to general fault isolation proce-dures, specific fault isolation procedures for the morecommon faults are also presented.

4-25. Responsibilities

Responsiblity for maintaining the DCS at a high levelof operation, rests not only with the DCS Stations andTechnical Controllers, but also with the user, the DCAand ACC Operations Centers, and Maintenance per-sonnel.

a DCS Station.(1) Each DCS Station is responsible for the

development of local fault isolation procedures basedon the particular type of equipment installed in thatstation, the design capability of each link or system,patch panel and test point appearances, and test equip-ment availability. The procedures clearly delineatethose functions which will be performed by technicalcontrollers and those which will be accomplished bymaintenance personnel.

(2) Each station should have ready referencecharts at or near each patch panel or test point show-ing the required teat tone level, the signal and noiselevels, and the allowable tolerance at that test point,This data is gotten from the technical evaluation madeat the time the equipment, link, or system was accepted.

(3) The requirement for maintaining the correct

TM 11-5895-1012-10

input or output signal levels cannot be over-empha-sized. One or two voice channels operating with exces-sive signal levels can disrupt the entire baseband Infact, high levels inserted into one channel can disruptother links or systems through which that signal isrouted. By the same token, a change in signal level atone point will affect the level at all subsequent pointsin the system. Signal level adjustments must not bemade without complete coordination with all locationsthat can be affected. equipment adjustments made byTechnical Controllers will normally be limited to oper-ational controls which are necessary for proper circuitor trunk operation; i.e., line current levels, compositeaudio levels, mode changes, channel reduction, orparalleling (twinning). They will not normally adjust,or attempt to adjust, any of the controls used forequipment alignment.

(2) When a &graded condition or other trouble isencountered at a given station, the Technical Control-ler of that station coordinates with distant stations,local users, and associated transmitting and receivingelements in his efforts to isolate and locate the fault.He has primary responsibility for this action, and mustreceive full cooperation from all other station Techni-cal Controllers involved. When it is determined thatthe fault is located at a distant station, or in a linkserving an area beyond that station, responsibility forlocating and correcting the fault is transferred to, andassumed by, the station Technical Controller primarilyconcerned.

c. User. The user is responsible for notifying the re-sponsible Technical Controller of all instances of serv-ice degradation evidenced by high data error rates, oc-casional noise bursts into the voice channels servinghim, or other indications of unsatisfactory conditions.The user renders free cooperative to the TechnicalController and the correction of service degradation.

d. DCA and ACC Operations Center.(1) The Operations Centers monitor the progress

of the station Technical Controllers in their trouble-shooting efforts, but under normal circumstances,does not actively engage in the isolation of a fault. Ifhowever, the station Technical Controllers encounterdifficulties and cannot restore service within a reason-able period of time, the active Operations Center is re-sponsible for assuming the overall direction of the cor-rective actions, for providing a workable solution tothe problem, and for keeping circuit outage time to anabsolute minimum.

(2) Troubles encountered on multichannel ormultilink circuits often are of an accumulative natureand present a complicated condition for resolution. Todetermine the cause, or causes of such a condition spe-cial link and segment tests may be required. The DCAand ACC are responsible for determining the require-ments for such special tests on the basis of station re

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ports. The Operations Center coordinates the tests,collects and analyzes the results, and directs remedialactions as necessary.

(3) Unless there are definite indications of a majorabnormality the Operations Center normally does nottake immediate action to inquire about circuit condi-tions, inasmuch as continuous inquiries by the Centerimpedes the troubleshooting and fault correction ac-tions of the station Technical Controller and mainte-nance personnel. The Operational Center is responsible,however, for investigating outages which have notbeen cleared after a reasonable period of time, or if noexplanation has been made by the remote stations orthe cognizant master station, and for rendering assis-tance in restoring service.

e. Maintenance Personnel. After faults have beenlocated and identified, maintenance personnel are re-sponsible for effecting necessary repairs and mainte-nance in accordance with appropriate technical man-uals pertinent to the particular item of faulty equipment.

4-26. F u n c t i o n a l A r e a s

a. For purposes of fault isolation, a Technical Con-trol Facility will fall into one of the following threefunctional areas:

(1) A Technical Control Facility which providesthe user with access to the Defense CommunicationsSystem; i.e., the serving TCF.

(2) A TCF which has voice frequency channelbreakout, but does not provide the user a direct accessto the DCS; i.e., a receive channel of one group is cross-connected to the send channel of another group..

(3) A TCF in which the signals appear at a groupor supergroup level, i.e., no vf channel breakout.

b. It is possible that a Technical Control Facilitycould be involved in more than one functional area atone time, depending upon the circumstances at thatparticular time and station configuration.

4-27. Troubleshooting Practices

a. Fault Notification. Technical Controllers arealerted to actual, or impending circuit outages bymeans of alarm indicator displays, by notificationfrom the user, of circuit deterioration or failure by adistant Technical Controller, and as the result of testing and monitoring.

(1) The supervisory alarm subsystems provide analarm when a failure occurs in various equipment andsystems at the DCS Station, such as single frequencysignaling equipment, ringers, multiplex systems, fusepanels, or the dc power system. When alerted to an ab-normal condition by an alarm, the Technical Control-ler and maintenance personnel must perform syste-matic step-by-step monitoring, or testing of the systemsegments into, through, and out of the station, in or

4-16

der to isolate the fault(s) to specific areas and/or equip-

tivate the supervisory alarms, and consistnoise bursts in the circuit data error rates,channel levels. Usually, these problems are brought tothe attention of the Technical Controller by the user.The Technical Controller performs monitoring andtesting routinely, as circumstances permit. However,when notified of degrading circuit conditions by theuser, other Technical Controllers, or maintenance per-sonnel, monitoring and testing of the degraded circuit

in the Technical Control areas, provide a means of se-quential access to circuits and groups between most ofthe major equipment in the station.

b. Service Restoration. The Technicalmust use every means at his disposal torupted service as expeditiously as possible. Thesemeans, when available, should be used in the followingorder of priority:

(1) If a spare channel is available, the TechnicalController should patch the user circuit or group into aspare, while isolating and correcting the defectiveequipment.

(2) If a fault is identified within an item of equipment for which a standby or spare is available, the substitute equipment should be used to restore disruptedservice while the defective equipment is being re-stored.

(3) During prolonged, or projected extended out-ages, the Technical Controller should request alternaterouting instructions. Rerouting or pre-empting is ob-tained from a list in the station SOP.

(4) As a last resort, the Technical Controllershould pre-empt lower priority circuits in order to re-store service for high priority users. Every circuit, in-cluding switchboard trunks as well as allocated cir-cuits, is assigned a priority of restoration which mustbe adhered to in channel restoration. Establishment ofthese priorities is performed on a worldwide basis bythe Defense Communications Agency.

C. Records and Reports. The Technical Controllerwho first determines that a fault exists or to whom afault is reported by a user, is responsible for coordinat-ing the fault-isolation activities with distant stationTechnical Controllers, and is responsible for appro-priate log entries and reports. When a fault has beenisolated, an explanation of the nature of the troublemust be entered in the reporting station log, and thedistant Technical Controller must be notified so thatthe entries for both stations coincide. All circuit out

TM 11-5895-1012-10

ages must be recorded on the appropriate station logs,of the duration of the outage time or the

cause of the fault. Specific instructions for reportingof stations are contained in Standard Operating Proce-dures published by DCA and ACC. Trouble reports(work orders) must be prepared for each equipment orcircuit failure. This work order will notify mainte-nance of the faulty or sub-standard equipment- Onlyby strict adherence to this procedure can proper rec-ords be maintained. Prompt, efficient repair of faultyequipment often depends upon the completeness andaccuracy of these symptoms described on the writtenworkorder.

d. Catastrophic Failure. Normally, the TechnicalControllers keep DCA and ACC informed of anticipat-ed, imminent, or existing service failures or degradedconditions which are beyond the local capability to re-store within a tolerable delay or outage time period. Inan exceptional case, a catastrophic failure conditionmay be encountered in which the alarm indicator dis-play may depict a number of simultaneous alarms orprovide an indication of a second major alarm withinthe same station before the first alarm has beencleared. In these cases, DCA or ACC may provide alter-nate routing instructions, or other solutions, as appli-cable.

4-28 . Fau l t I so la t ion Procedures

The guidelines contained in paragraphs 4-29 through4-34 are for use in preparing local procedures and indetermining the location of the equipment or mediawhich is causing signal degradation. It may not be nec-essary to take each step in the order listed. Dependingupon the trouble indications, it is possible that somesteps may be taken in different sequence, combinedwith other steps, or even eliminated completely. ATechnical Controller’s first questions, when a problemis recognized, should be “Does the problem affect onlya single circuit or channel, or the entire group or super-group?” and then, “Is the circuit, group or supergroupmeeting the standards through my station?” The Tech-nical Controller must then take the actions necessaryto answer those questions. All steps will be taken incomplete coordination with the other stations throughwhich the signal is routed, and with the local mainte-nance activity.

a. Fault isolation should proceed from the point offault recognition toward the signal source to the pointwhere the fault exists. Results of in-station checks willbe completely coordinated with the other concernedTCF's and the trouble corrected at the source. Adjustments will not be made at intermediate points to com-pensate for a problem generated at some other point inthe circuit or system.

b. In the event a known fault cannot be correctedwithin a reasonable amount of time (i.e., 10 minutes),

the Technical Controller should reroute or restore inaccordance with established restoration priorities,pending completion of repairs. Difficulties encount-ered in obtaining a reroute path will be reported to theappropriate DOCC and reroute instructions will be re-quested.

4-29 . Voice Frequency Fau l t I so la t ion

When a Technical Controller discovers that a circuit ora multiplex group is not operating within establishedparameters, in-service monitoring tests should be per-formed in accordance with established station proce-dures. This will help determine whether a single chan-nel, an entire group or supergroup, or the baseband isaffected. In addition, whether the fault is located with-in the station multiplex or line conditioning equipment. Time is important. The goal is to locate and cor-rect the fault before the users service becomes unuse-able.

a. In coordination with the distant station(s) and theappropriate control office(s), using available order-wires, selective elimination of each portion of the cir-cuit may be used to locate the fault area. In-stationmonitoring procedures will locate the fault specificallyenough to permit the Technical Controller to modifyestablished fault isolation procedures and attack theproblem directly, either by substituting for the faultyitem, or by making a patching substitution. Thenthrough the use of out-of-service testing procedures, orthe in-station test and alignment procdures, correctthe problem.

b. Keep in mind that the fault isolation proceduresestablished, serve only as a guide for efficient techni-cal control operations and do not represent a rigid se-quence of steps which must be followed to solve a prob-lem. The Technical Controller should by-pass any un-necessary steps in order to quickly locate the fault andrestore normal service.

4-30. Single Voice Frequency ChannelF a u l t

When it is determined that a single voice channel of avoice frequency group is unuseable or deteriorated, thestation Technical Controller will take the following ac-tion:

a. Coordinate with the distant station TechnicalController to transfer service to a spare channel, orpreempt a lower priority user if required. If a low pri-ority user is preempted, have the distant station Tech-nical Controller notify the low priority user of the pre-emption.

b. Request the distant station Technical Controllerto send a test signal on the faulty channel in accord-ance with the appropriate out-of-service test procedureafter the traffic signal has been moved to anotherchannel.

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4-31. Multichannel Fault

following actions:a Determine whether alternate equipment is avail-

able for substitution.b. If none is available, notify the distant station

Technical Controller to block the use of the faultychannels, and to send test signals on specific channels,preferrably on voice frequency channels 1, 6, and 12 ofthe affected group.

c. Notify local users of circuit failure.d. Monitor the test signals transmitted by the dis-

tant Technical Control Facility. In conjunction withstation maintenance personnel, coordinate mainte-nance necessary to restore the multiplex group orsupergroup equipment to proper transmission stand-ards by alignment, replacement, or repair. If the mal-function cannot be isolated or corrected within a rea-sonable length of time (i.e., 10 minutes), service will berestored in accordance with established proceduresand assigned restoration priorities.

e. When the malfunction has been isolated, cor-rected, and the circuits checked out, notify the distantTechnical Control of the nature of the problem endrequest removal of test signals. If necessary performadditional out-of-service testing to ensure that all cir-cuits meet specified parameters.

f. Restore user service to normal routing.g. Complete station records, trouble reports, log en-

tries, etc., in accordance with established procedures.

4 - 3 2 . B a s e b a n d F a u l t

When it is determined that the entire transmissionmedia baseband has deteriorated, the station Techi-

f. Measure the group regulation pilottransmission media monitor jacks with

selective voltmeter and spectrum analysis at bothterminals. Make certain that the levels are in accord-ance with appropriate subsystem block and leveldiagram and that they are free of noise.

frequency signal, asis excessively noisyindications at the

(i.e., 10 minutes), the Technical Controller shouldnotify the appropriate DOCC and request reroutinginstructions for any priority circuits that may be in-volved.

h. Connect a frequency selective voltmeter and aspectrum analyzer to the transmission media basebandmonitor jack to test for interference or man-madenoise at the receive terminal. Observe the basebandsignal for noise pulse or interfering signals.

i. Work with the maintenance personnel as they al-ternately deactivate the individual receive while ob-serving the baseband signal and multiplex perfor-mance to determine the frequency sensitivity (inter-fering effect) of unwanted signals or to isolate a defec-tive receiver.

j. Request alternate deactivation of the frequencydiversity transmitters to ensure that unwanted signalsor noise are not caused by the distant end transmit-ters. Direct maintenance personnel to perform trans-mitter and common baseband equipment tests toverify normal operation.

k. If the fault has not been isolated at t&is point inthe test procedure, request deactivation of both trans-mitters. Monitor the receiver output on the oscillo-scope and the automatic gain control (AGC) meters.The presence of noise spikes or pulses indicates eitherradio interference or local man-made noise. Noise maybe caused by many things, including defective antenna

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TM 11-5895-1012-10

o r e q u i p m e n t to more than one receiver.l. Direct maintenance personnel to perform receiver

common base-band equipment tests to verify nor-operation.

m. Test the common circuitry of the multiplex ter-minal.

n. When the malfunction has been isolated and cor-notify the distant Technical Controller of theof the problem and request removal of the test

signal. If necessary perform additional out-of-servicetesting to ensure that all circuits meet specified

o. Restore user service to normal when the correc-tive action has cleared the malfunction.

p. Complete station reports, trouble reports, log en-tries etc., in accordance with the established proce-dures.

4 -33 . Dc Fau l t I so la t ion

When the Technical Controller discovers that one ormore dc circuits are not operating properly, in-servicemonitoring tests should be performed in accordancewith established station procedures to determine if asingle channel or the entire VFCT group is faulty. Ifthe entire VFCT group is affected, the Technical Con-troller must continue monitoring to determinewhether the fault is within the voice frequency subsystem, the multiplex channel equipment, or the localor distant VFCT equipment. If the fault is not in theVFCT equipment, the controller should refer to para-graphs 4-28 through 4-32 and apply the applicableprocedures. Multichannel faults not involving thevoice frequency subsystem or multiplex channel equipment are limited to send or receive VFCT equipment.The Technical Controller should proceed immediatelyto effect isolation of the fault within the portions ofthe VFCT which are common to all channels. Single dcchannel faults may be located by coordinating with thedistant station to selectively eliminate each portion ofthe circuit which is performing properly. In-stationmonitoring procedures may often locate the fault to ageneral area which will permit a modification of thefault isolation procedures and attack the problemdirectly, either by substitution of equipment by patch-ing or replacement of equipment. Out-of-service test-ing procedures or in-station test and alignment proce-dures can then be applied to locate and correct thefault.

a. When it is determined that one channel of amultichannel VFCT system is unuseable, the Techni-cal Controller should proceed as follows:

(1) Coordinate with the distant Technical ControlFacility to restore service on a spare channel or pre-empt a low priority user. If a low priority user is pre-empted, have the distant Technical Controller notifythe user of preemption of the circuit.

(2) Request the distant Technical Control Facilityto send a teat signal on the faulty channel.

(3) If the results of the test procedure are unsatis-factory at a certain point, the trouble will have beenisolated to that particular area. In such a case, proceedas follows:

(a) In coordination with the distant technicalcontrol, determine which equipment is at fault (for ex-ample, VFCT keyer or converter, line conditioningequipment, etc.).

(b) Coordinate the equipment repair or align-ment required tocorrect the fault.

(c) If equipment is found to be unuseable, coor-dinate with station maintenance personnel for its re-placement.

(d) After repair or replacement, perform the ap-propriate test to ensure proper operation of the circuit.

(e) Notify the user that the fault has beencleared, and restore service to the normal route. Serv-ice shall always be returned to the normally assignedchannel at the earliest possible time.

(4) When the test signal from the distant TCF issatisfactory, request a test signal from the distant subscriber to determine whether the fault is between thedistant subscriber and distant Technical Control Facil-ity or between the local TCF and its subscribers. TheTechnical Controller at both ends of the circuit shouldmonitor the subscriber’s test signal, and in that wayisolate the fault area.

(a) Coordinate the repair or alignment requiredto provide service between the DCS Station and thelocal subscriber.

(b) Perform the appropriate tests to ensureproper operation of the circuit over the lines betweenthe DCS Station and the local subscribers.

(c) Notify the user that the fault has beencleared, and restore service to the normal route.

(5) Complete station records, trouble reports, logentries, etc., in accordance with the established proce-dures.

b. When it is determined that all channels within amultichannel VFCT system are unuseable, the Techni-cal Controller shall proceed as follows:

(1) Notify the distant Technical Control Facilityto block user input on all channels. Notify users thatthe circuit has failed, and deactivate all traffic equip-ment.

(2) The cause of failure could be in the voice fre-quency channel or in the VFCT equipment. Performthe voice frequency fault isolation procedures as de-scribed in paragraph 4-30.

(3) If the results of (2) above are satisfactory, re-quest the distant TFC sent a test signal on specificchannels. Channels 1, 8, and 16 of the VFCT equipment are preferred test tone channels. Proceed as fol-lows:

4 - 1 9

TM 11-5895-1012-10

(a) Check the level of the multichannel VFCT

tones at the voice frequency patch panel and instruct

(4) When the trouble has been isolated and cor-rected by coordinating the maintenance necessary torestore operations, notify the distant Technical Con-troller of the nature of the problem and restore theuser circuits to normal. .

(5) If the malfunction cannot be corrected in areasonable length of time (Le., 10 minutes), the Tech-nical Controller should notify the appropriate DOCCand, if required, request rerouting instructions for pri-ority channels pending the completion of repairs.

(6) Complete station records, trouble reports, logentries, etc., in accordance with established proce-dures.

4-35. Examples of Voice Channel FaultI s o l a t i o n P r o c e d u r e s4-34 . Commerc ia l P r o c e d u r e s

Initial testing will be conducted to determine whetherthe reported trouble is in the local terminal portion,distant terminal portion, or in the leased portion of thecircuit. So that such testing can be accomplished, it isessential that all parties concerned definitely under-stand the extent of their responsibility.

a.ing

Military terminals are responsibleproper circuitry, correct operation

for establish-of equipment

and circuitry from and to the terminals where thecommercial carriers responsibility begins at the inter-face points.

b. The commercial carrier is responsible for estab-lishing and maintaining the type of service requestedby the military between the designated terminals. Thisincludes troubleshooting and restoration of service upto the interface points. The following action will betaken:

(1) Call the appropriate commercial circuit controloffice for trouble reporting.

(2) Provide an account of the trouble indicated ac-cording to results obtained from tests.

(3) The nature and indications of commontroubles encountered on leased or military circuits arelisted below. The terms listed have been chosen so thatthe nature of the trouble will be understood by com-mercial carrier personnel throughout the world whohave contact with the DCS.

(a) No receive current or signal.(b) Cannot receive ringing current.(c) Levels too low.(d) Excessive noise.(e) Intense crosstalk.

(3) Telephone numbers.(4) Date, time and trouble number.(5) Station reported to.(6) Names or initials of coordinator.

d. Inquiries concerning status of reported

carrier will provide information asconcerning the status of the circuit

The commercial carrier may include probably locationof trouble switch to an alt-route, but they are notrequired to furnish more detailed information. Onlyinformation concerning restoral of circuit or in-effect

between the commercial

There are a number of acceptable methods of isolatinga faulty link in a communications channel. Two meth-ods are explained in this paragraph . The first method(discussed in a and b below) requires the isolation pro-cedure to begin at the point of fault recognition. Eachsite clears itself of any responsibility for fault by

sponsible TCF to isolate the fault over the whole com-munications chain by having the signal from the localTCF looped back and tested at various points in succes-sion along the chain

a. Noise Burst on Multiplexed Through Circuit. Theprocedure followed is outlined in flow-chart fashion infigure 4-7. Th tant Technical Controller is notifiedthat noise bursts are being received by a subscriber.The complaint has been verified at the distant end,and that station has been cleared of causing thetrouble. The noise bursts are incoming to the distantTechnical Control Facility, and that Technical Con-troller requests that the local Technical Controllerclear the local station of being the cause of the noisebursts. The local controller is responsible for simplychecking the circuit through the site to determine ifthe fault source is in the station, reporting back to thedistant station, and correcting the fault if necessary.Following is an example of an isolation procedure forthis type of fault:

(1) At the equal level patch panel farthest fromthe complaining subscriber, connect a loudspesker tothe receive monitor jack of the affected circuit.

(2) Listen for the noise burst complaint.

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TM 11-5895-1012-10

action to clear the problem, responsibleTechnical Control Facility of the source of the trouble,action taken, and complete station records in accord-ance with established procedures.

(9) If, after maintenance personnel have checkedthe equipment, the source of trouble is not at the localstation, notify the responsible TCF so that fault iso-lation may continue at points closer to the signal

(10) Standby to assist in patching o rother fault isolation tests if it should be necessary.

(11) If noise is not present, then the source oftrouble is somewhere between this point and the com-plaining subscriber. This includes the local stationtransmit multiplex and transmission media equipment

Figure 4-71. Noise Burst on multiplexed through circuit, fault isolation flow chart (sheet 1 of 2)

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TM 11-5895-1012-10

(12) Perform the tests described in (1) through (3)above at the equal level patch panel closest to the com-plaining subscriber.

(13) If noise bursts are present, then the trouble islocated somewhere within the local TCF. The respon-sible Technical Control Facility and local maintenancepersonnel should be notified. Take action to clear thefault and report in accordance with established stationprocedures.

(14) If noise bursts are not present, request thatlocal maintenance check the transmit side of the cir-cuit towards the complaining subscriber for the pos-sible sources of trouble. Should the local station trans-mit side be faulty, take action to have the troublecleared and consider what action must be taken, simi-lar to that outlined in (7) above.

(15) Notify the responsible TCF of the source oftrouble, action taken and complete station records inaccordance with established procedures.

with established procedures.b. Noise Burst on a Local Subscriber Circuit. The

procedure followed is outlined in flow-chart fashion infigure 4-8. The Technical Controller is notified by aconnected subscriber that frequent noise bursts arebeing received. The local Technical Controller hasresponsibility for coordinating fault isolation pro-cedures at distant station which may be involved; but,first if must be determined whether the local station isat fault. An immediate decision must be made whetherto patch the affected circuit over to a spare channelThis decision is influenced by the priority of the circuit

Figure 4-72. Noise burst on multiplexed through circuit, fault isolation flow chart, (sheet 2 of 2)

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TM 11-5895-1012-10

at this point indicates the fault lies between thelevel patch panel and the signal source. This

encountered, proceed to (6) below.(3) Notify local maintenance personnel of the

problem and request the multiplex equipment beis local. If the fault is

trouble by substituting for the defective channelequipment. If the noise is found to be across the entiregroup, consider patching at the group level, replacingdefective equipment, or if the outage may be long induration, (i.e., longer than 10 minutes), rerouting cir-cuits in accordance with established procedures andpriorities.

(5) After the fault is cleared, restore any rerouted

Figure 4-81. Noise burst on a local subscriber circuit, fault isolation flow chart (sheet 1 of 3).

4 - 2 3

TM 11-5895-1012-10

circuits to their normal path. Complete station records coordination with other TCF's whichin accordance with established procedures. defective circuit.

(6) If the local station proves not to be the source (7) When the troubleof trouble, as the responsible TCF, proceed with rerouted circuits to theirestablished fault isolation procedures through son for and location of

Figure 4-82. Noise burst on a local subscriber circuit, fault isolation flow chart (sheet 2 of 3).

4 - 2 4

TM 11-5895-1012-10

(11) Notify local maintenance personnel of theproblem. When the troulbe has been cleared, removeany patches which have been established. Completestation records in accordance with establishedprocedures.

(12) If noise is not encountered at the equal levelor primary patch panels, the fault is in the subscriber'sterminal equipment or the tie-cable.

. (13) Notify local maintenance personnel andlocate a spare cable pair.

(14) If extended circuit outage time is expected,

Figure 4-83. Noise burst on a local subscriber circuit, fault isolation flow chart (sheet 3 of 3)

4 - 2 5

TM 11-5895-1012-10

(15) After the fault has been cleared, remove anypatches which have been established and complete sta-tion records in accordance with established proce-dures.

c. Fault Isolation of a VF Subscriber Circuit by theLoop-Back Method. This procedure followed is outlinedin flow-chart fashion in figure 4-9. The TechnicalController is notified by a local subscriber that the cir-cuit level is not correct. A spare channel is availableand the circuit is patched over onto the spare circuit sothat the normal path can be available for out-of-servicetesting. The basic procedure is to clear the local station

send point of the same channel under test at the equallevel patch panel.

(3) The local Technical Controller inputs a 1Hz test tone on the send circuit at a level of 0 dBm atthe equal level patch panel. The same test tone should

Figure 4-91. Vf subscriber circuit loop-back, fault isolation flow chart (sheet 1 of 2)

4 - 2 6

TM 11-5895-1012-10

that channel's receive circuit onpanel at a level of 0 dBm. If theleg of the defective channel has

If the level is not correct, the fault hasisolated between the two TCF’s and the trouble

can be turned over to maintenance personnel.(4) If the tone looped back is received at the

proper level, the distant TCF is requested to removethe loop back patch and the next TCF further towardthe signal source is requested to perform a similarpatch. Again the local TCF inputs a 1000 Hz tone at0 dBm and measures the level of the looped back tone.Following this procedure, trouble can be isolated be-tween any two equal level patch panels in the channel.

(5) When the fault has been located in the de-fective circuit, the tasks is turned over to maintenancepersonnel to clear the trouble. After the fault has beencleared, restore the circuit to its normal path, obtain

the reason for the fault and location, and complete sta-tion record% in accordance with established pro=cedures.

4-36 . Examples o f a Dc Ci rcu i t Fau l t I so -l a t i o n P r o c e d u r e s

a. Open Circuit Condition. The station TechnicalControl Facility is notified by a connected telegraphsubscriber that incoming traffic has been interruptedand that the printer has started to run open.Reference to the circuit layout record card indicatesthat the subscriber circuit is connected by cable to anearby military installation. The most likely reasonfor the condition reported is a break in the dc loopcawed by failure of the loop battery, an open connec-tion at the subscriber terminal, a defect in the cable, oran electrical failure of the receiving equipment.

(1) Loop Battery Check. The Technical Controller

Figure 4-92 . Vf subscriber circuit loop-back method, fault isolation flow chart (sheet 2 of 2)

4 - 2 7

TM 11-5895-1012-10

should check the appropriate fuse panel (or associatedalarm output) to verify that no failure has occurred inthe loop current distribution system serving thesubscriber loop and associated DLIU. If, in fact, ablown fuse alarm is received, the line should bechecked for a short circuit. If no short is detected, theDLIU should be substituted and refused.

(2) Open Connection at Subscriber Terminal. If nofailure in the loop battery supply is detected, the Tech-nical Controller should:

(a) Locate the jack appearances of the sub-scriber circuit at the dc primary patch panel and con-nect a current meter into a monitor jack appearance ofthe transmit circuit (receive circuit of subscriber) tomeasure the loop current.

(b) If no loop current is observed, connect avoltmeter into the receive monitor jack appearance ofthe defective circuit on the dc equal level patch panel.Measure for a steady mark condition from the VFCTequipment.

(c) If a steady mark condition is obtained,substitute the DLIU through patching operations. Per-form the test in (a) above. If no loop current ismeasured, proceed to(g) below.

(d) If loop current is measured, notify mainte-nance personnel of the defective DLIU.

(e) Complete station records in accordance withestablished procedures.

(f) After maintenance personnel have either re-paired or replaced the defective DLIU, return the cir-cuit to its normal routing.

(g) If no loop current was measured in (c) above,the TCF interface equipment is not at fault. The breakis somewhere in the dc loop between the station andthe subscriber.

(h) Return the normal interface equipment tothe circuit by removing the patchcords.

(i) Isolate the defective subscriber loop from thein-station circuits by inserting a shorting-type dummyplug in the line transmit jack on the dc primary patchpanel.

(j) Request that user maintenance personnelcheck the continuity of the subscriber loop.

(k) Upon verification that maintenance per-sonnel have located and corrected the fault, insurethat the normal TCF interface equipment is connectedto the subscribers circuit.

(l) Remove the dummy plug from the linetransmit jack to reconnect the subscriber to the in-sta-tion circuit.

(m) Measure the loop current at the dc primarypatch panel to ensure the circuit is operating normally.

(n) Complete station records in accordance withestablished procedures.

(3) Defective Cable. The Technical Controller isnotified that the reason for the open circuit condition is

a break in the cable between the DCS station and thesubscriber. The report indicates that the cable will beout-of-service for some period of time. The TechnicalController reviews the area circuit records and theyindicate that an alternate link is not available, or feasi-ble, between the two communicating locations. Further, it is not practicable to copy the incoming trafficat the TCF for use by the subscriber. The TechnicalController should take the following action:

(a) Contact the distant Technical Control Facil-ity and request that traffic be stopped to the subscriber until the fault has been cleared.

(b) Insert a dummy plug into the line transmitjack (the subscribers receive circuit from. the TCF) atthe dc primary patch panel. This will isolate the subscriber loop from the in-station circuit.

(c) Upon notification by maintenance personnelthat the cable has been repaired, the Technical Con-troller should remove the dummy plug from the linetransmit jack at the dc primary patch panel to recon-nect the subscriber loop to the in-station circuit.

(d) Notify both the subscriber and the distantTCF that the circuit is ready for the passing of traffic.

(e) Complete station records in accordance withestablished procedures.

(4) Defective Subscriber Terminal Equipment.The Technical Control Facility is notified by main-tenance personnel that the reason for the open circuitcondition is an electrical failure in the receiving equip-ment at the subscriber terminal. The Technical Con-troller should take the following actions:

(a) Insert a dummy plug into the line transmitjack (subscribers receive circuit from the TCF) at thedc primary patch panel to isolate the subscriber loopfrom the in-station circuit.

(b) Notify the distant TCF that the circuit isout-of-service and stop traffic from being transmittedto this subscriber.

(c) Upon notification by maintenance personnelthat the equipment failure has been corrected, theTechnical Controller should remove the dummy plugfrom the line transmit jack appearance at the dcprimary patch panel to reconnect the subscriber loopto the in-station circuit.

(d) Provide a Fox test as required, so that main=tenance personnel can ascertain that the receivingequipment is adjusted properly.

(e) Complete station records in accordance withestablished procedures.

b. Defective VFCT Channel Equipment. The Tech-nical Control Facility is notified by a connected subscriber that service has been interrupted on the receivecircuit. The Technical Controller initiates fault isola-tion procedures. A zero indication is shown when avoltmeter is inserted in a monitor jack of the subscrib-er receive channel at the dc equal level patch panel.

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The Technical Controller then actuates the cut-key ofthe receive channel on the dc equal level patch panel.If a cut-key is not available, the Technical Controllerinserts a dummy plug into the receive channel jack ap-pearance at the dc equal level patch panel. This actionapplies hold battery current to the loop, which pre-vents the receive equipment from running open. TheTechnical Controller can then proceed with the follow-ing fault isolation procedure to determine if the faultexists in the VFCT channel equipment, either in the lo=cal station or at a distant terminal.

(1) Consult the station circuit files and identifythe voice frequency and tone channel assignments ofthe dc subscriber circuit which is in trouble.

(2) Place the selector switch of the teletype carriertest set to the designated tone channel, and connectthe unit to the voice frequency equal level patch panelLINE transmit jack serving that channel of the VFCTequipment.

(3) Patch the dc output of the VFCT terminal atthe dc equal level patch panel to a distortion analyzer,distortion test set or a monitor teleprinter. Jack ap-pearances for these items of equipment appear on themiscellaneous/interbay jackfields of the dc test bays. Ifteletype signals are not received at this point, a failurein the local VFCT channel equipment is indicated. Ifthe VFCT passes the test signal, then the fault lies inthe voice frequency area or at the distant terminal (cbelow).

(4) If the local VFCT equipment fails the test in(3) above, request that station maintenance personnelcheck the VFCT channel equipment serving the subscriber loop.

(5) The local Technical Controller should coordi-nate the transfer of the subscriber circuit to a sparechannel, if necessary with the distant station Techni-cal Controller.

(6) Upon correction of the fault, the local Techni-cal Controller should take action to return the subscriber circuit to its normal routing. To prevent un-necessary loss of traffic on the circuit, the patchcordsat both ends of the circuit should be removed simul-taneously.

(7) Complete station records in accordance withestablishedprocedures.

c. Failure at Distant Terminal. If signals are detect-ed during the test in b(3) above, and the local voice fre-quency channel equipment serving the VFCT checkgood, a failure in the VFCT at the distant station is in-dicated. The local Technical Controller should do thefollowing:

(1) Contact the Technical Control Facility at thedistant VFCT terminal and request that he continuethe fault isolation procedure through the distant sta-tion. This procedure must be continued by all Techni-cal Control Facilities involved with the circuit until

the fault has been isolated.(2) Upon isolation of the fault at a distant station,

the responsible Technical Controller should coordinateefforts to restore service to the subscriber. The tempo-rary transfer of the circuit to a spare channel may berequired.

(3) Upon notification that the necessary repairshave been made, the responsible Technical Controllershould assist the distant Technical Controller(s) in therestoration of normal service to the subscriber.

(4) Complete station records in accordance withestablished procedures.

d. Channel Degradation. The local Technical Con-trol Facility is notified by a connected subscriber thata teletypewriter machine has started to producegarbled page copy. The report states that the error rateis serious enough to render incoming messages unintel-ligible. The local Technical Controller should proceedas follows:

(1) Subscriber Loop Check. The local TechnicalController should patch a monitor teleprinter into aMONITOR jack appearance of the complaining subscriber receive channel at the primary dc patch panelto determine the quality of the signals passing throughto the subscriber loop. An alternate method is to patcha distortion analyzer into the subscriber circuit at thispoint to determine the type of distortion causing thesignal degradation. This information is most useful inmany instances in identifying the origin of a fault con-dition. Illustrations of normal and distorted teletypesignals are contained in the instruction manual for thedistortion analyzer.

(2) Range Setting Check. If the telegraph signalsare copied without garbling during the subscriber loopcheck, the reported fault condition may be caused byan improper range setting of the subscriber teletypemachine and this should be checked. If the copy isgarbled proceed to (3) below:

(a) Request the subscriber to standby for a testtransmisssion to evaluate the adjustment of the tele-type machine.

(b) Patch a pattern generator output into theLINE jack appearance of the subscribers receive cir-cuit (transmit from the TCF to the subscriber) at theprimary dc patch panel. Transmit a Fox test messageto the subscriber station. The range control of the subscriber teletypewriter machine should be adjusted bymaintenance personnel to the midpoint of the rangeover which perfect page copy is obtained.

(c) Upon correction of the fault, complete sta-tion records in accordance with established proce-dures.

(3) DLIU Check. If the monitor teleprinter pro-duces garbled page copy when patched into the subscriber circuit, the Digital Line Interface Unit shouldbe checked for faulty operation. The Technical Con-

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troller should proceed as follows:(a) Patch the monitor teleprinter into the MON-

ITOR jack appearance of the subscriber’s receive cir-cuit at the dc equal level patch panel. A defectiveDLIU is indicated if perfect page copy is obtained atthis point. If not proceed to (4) below.

(b) Temporarily replace the normal DLIU with aspare unit through patching operations.

(c) Request that local maintenance personnel re-pair the defective unit.

(d) When the repaired DLIU is returned to thenormal channel assignment, the Technical Controllershould remove any temporary patches which weremade to restore service to the subscriber.

(e) Complete station records in accordance withestablished procedures.

(4) VFCT Channel Equipment Check. If the moni-tor teleprinter connected in (3)(a) above produces gar-bled page copy, the isolation procedure should con-tinue following the procedure outlined in b above.

(5) Distant Terminal Check. If the degraded signalis present in the voice frequency signal ((4) above) a de-fect in the VFCT equipment at a distant station is indi-cated and the fault isolation should continue followingthe procedures outlined in c above.

4-37. Circuit Status

The duty supervisor of the Technical Control Facilitymust know at all times the status of circuits and equip-ment removed from service because of failure or substandard performance. Positive action must be takento ensure that:

a. Notification is made when a circuit is determinedto be below acceptable quality standards and is to beremoved from service to restore it to an acceptable lev-el. This notification should include the status of thefollowing actions:

(1) The appropriate control offices have been noti-fied.

(2) That service has been restored using a sparechannel.

(3) That a spare channel is not available, and serv-ice to the user has been temporarily interrupted.

(4) That a spare channel is not available, and serv-ice is restored by preemption of a lower priority user.The prerempted circuit must be identified by CCSD.

b. When user service must be interrupted, the Tech-nical Controller coordinates with the local mainte-nance activity for initiation of immediate repair ac-tion.

c. Periodic progress reports on the restoration ofservice will be provided to the duty supervisor so thathe can assure that the circuit is returned to service as

rapidly as possible.

4-38. Restoration

Individual circuits are restored in accordance withtheir assigned restoration priority.

a. R&oration of service to users can basically be ac-complished by repairing or replacing faulty equipment, rerouting the circuit around the disrupted seg-ment of the circuit by using spare facilities, or by pre-empting a lower priority circuit to make a higher pri-ority circuit good. In order to maintain continuity ofservice for all users of the DCS, the correction ofequipment should be used in lieu of preempting anoth-er working circuit when the time required by eachmethod is nearly the same. Where trouble in a highpriority circuit has been localized to the transmissionmedia between two circuit end points and lower priori=ty circuitry exist between these two points, the lowestpriority circuit(s) should be preempted if this willrestore the higher priority circuit in substantially lesstime than the other methods of restoration.

b. To assist the Technical Controller in visualizingthe additional possible reroute paths available, blockdiagrams will be prepared at each Technical ControlFacility for the area of interest, showing links betweenconnected stations and any appropriate extensionthat would permit a reroute to be made. These dia-grams should be maintained in a conspicuous location.

c. C-reference data will be prepared to permitproper designation of facilities required during coordi-nation for the r&oration of service. For example,commercial numbers will be used to identify circuits tocommercial agencies. The cross-reference file will bemaintained in a position readily accessible to the Tech-nical Controller on duty.

d. Within the DCS, Technical Controllers will, whenaccomplishing control action& refer to circuits byCCSD, and will refer to trunks by the DCS trunknator. In all cases, it is essential that Technical Con-trollers use equipment nomenclature and languagethat is readily understood.

e. The primary responsibility for reroute action nor-mally rests with the receiving Technical Control Facil-ity. The appropriate control office will be notifiedwhen reroute action cannot be accomplished.

f. When the trouble on the original path of a rerout-ed circuit has been cleared and tested, the TechnicalControl Facility initiating the reroute will take actionto have the circuit returned to its original use and con-figuration. Also, this TCF will take action to returnthe path, used for the reroute to its original use andconfiguration.

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Section V. MANCESTANDARDS AND TEST MEASUREMENTS4-39. General

This section contains the DCS Technical Schedules,which provide circuit performance parameters. Chap-ter 6 contains the associated test descriptions for testmeasurements of DCS facilities, systems, or circuits.In addition this section provides guidance for testingDCS circuits to determine compliance with DCS Tech-nical Schedule criteria and to determine circuit signal-ing performance.

4 - 4 0 . Technical Schedules

The DCS Technical Schedules are itemized listings ofall the common services and circuit parameters provid-ed by the DCS. The DCS Technical Schedules apply toall government-owned circuits within the DCS withthe exception of voice circuits provided over high fre-quency radio. Table 4-1 describes the type of serviceprovided by each circuit performance code. Tables 4-2and 4-3 are a list of performance parameters requiredby each parameter code. Table 4-4 is a list of leasedservice performance parameters which common car-riers generally provide. These tables are samples andcurrent procedural documents should be checked forcurrent requirements.

a Government-owned circuits are required to meeteach parameter for the type of service specified in theTSO. Government-owned circuits unable to meet theDCS parameters, even with optimum transmission ad-justment, will meet the requirements specified by theDCA.

b. Leased circuits will meet all parameters guaran-contract, as applicable. U.S. common

tly guarantee frequency response andenvelope delay distortion parameters only. All other

parameters, unless specifically guaranteed by con-tract, are provided by the carrier on a “will-strive, non-guaranteed" basis; however, a circuit cannot be re-moved from service because of failure to meet theseother parameters unless the user reports unsatisfac-tory service and a nonguaranteed parameter is causingthe unsatisfactory service.

c. Leased circuits terminating in a military Techni-cal Control Facility or Patch and Test. Facility at bothends will be tested for the parameters in table 4-2 forthe type of service specified in the TSO. The commoncarrier will meet guaranteed parameters and will berequested to meet all other parameters. If the commoncarrier declines to meet these additional parametersand the user states that the circuit provides acceptableservice, the CCO will accept the circuit and identify allout-of-tolerance parameters in the in-effect report.

d. Leased circuits terminating in a military TCF orPTF at one end and a commercial test facility at theother end will meet the parameters guaranteed by tar-iff or contract, as applicable. The TCF or PTF will re-quest the carrier to test for all other parameters intable 4-2 for the type of service specified in the TSO.The CCO will identify in the ineffect report those pa-rameters the carrier declines to test.

e. Commercial circuit parameters and identifiersvary throughout the world and it is impractical to attempt to list all of them in this manual. Table 4-3 con-tains parameters and identifiers generally recognizedby the U.S. common carriers for conditioned circuits.DCA areas will compile a listing of commercial circuitparameters and identifiers used within their area of re-

Table 4-1. DCS Technical Schedules

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Table 4-1. DCS Technical Schedules-Continued

4 - 3 2

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Table 4-1. DCS Technical Schedules-Continued

Table 4-2. DCS Technical Schedules Circuit Parameters

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Table 4-2. DCS Technical Schedules Circuit Parameters - Continued

Table 4-3. DCS Technical SchedulesCircuit Parameters Z1, Z2, and Z3

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Table 4-3. DCS Technical Schedules Circuit Parameters Z1, Z2, and Z3 - Continued

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4 8 12 16 2 0 2 4 2 8 32 3 6 4 0 4 4 4 8 52 5 6 6 0 6 4 6 8 7 2

FREQUENCY (KHz)

NOTES:

1. ABOVE CURVE REPRESENTS ENVELOPE DELAY REQUIREMENTS. LIMITS ARE NOTSPEClFlED BELOW 6 KHz.

2. IF THE ENTIRE CIRCUIT CONSISTS OF PROPERLY AMPLITUDE EQUALIZED TWISTED

PAIR CABLE, FROM WHICH ALL LOADING COILS AND BRIDGE TAPS HAVE BEENREMOVED, NO DELAY EQUALIZATION SHOULD BE REQUIRED. GIVEN THE CORRECTFREQUENCY RESPONSE OVER THE RANGE OF .01 TO 50 KHz (NO DISCONTINUITIESOR SHARP ROLLOFFS), ENVELOPE DELAY WILL NOT NORMALLY BE AN ITEM FORCONCERN ON CABLE PAIRS.

3. SHOULD THE CIRCUIT CONTAIN CARRIER FACILITIES, DELAY EQUALIZATION MUSTBE EMPLOYED SUCH THAT THE DELAY VERSUS FREQUENCY RESPONSE OF THECIRCUIT IS A SMOOTHLY AND CONTINUOUSLY INCREASING FUNCTION OFFREQUENCY, WHICH FALLS WITHIN THE SHADED AREA OF THIS FIGURE.

E L 3 Z 0 0 4 6

Figure 4-10. Relative envelope delay vs frequency limits.

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Table 4-4. Commercial Technical Schedules

Note 1. Schedule 4A parameters are the same as C1 parametersNote 2. Schedule 4B parameters are the same as C2 parametersNote 3. Schedule 4C parameters are the same as C3 parametersNate 4. CCITT M.102 parameters are the same as C2 parameters, except that loss IS relative to 800 Hz instead of 1000 HzNote 5. DCS Technical schedules S1 and D1 compare to Commercial C2 Technical schedules for frequency response and envelope delay die

tortion.Note 6 DCS Technical schedule S3 compares to Commercial C5 Technical schedules for frequency response and envelope delay distortion

4-41. Test Descriptions

Each Test Description (TD) includes the test arrange-ment, equipment configuration, and test procedure.With the exception of those parameters which are notapplicable to all types of channels, each analogparameter test description includes date for testingthe following types of channels: voice frequency chan-

channels (0-50 kHz), 48 kHz channels

4-42. Digital Distortion Standards

The digital distortion standards contained in this para-an extract from other publications. It isthat some equipment currently used in the

will nut operate within these standards. Each

DCS facility using substandard equipment shoulddetermine the technical reasons why the equipmentwill not operate within established standards, anddetermine a standard which the equipment can con-sistently meet. As a minimum, equipment will at leastmeet the specifications contained in the technical ormanufacturer manual, where specified. Requests forwaivers from DCA performance standards will be submitted through appropriate DCA regions to cognizantDCA areas for approval, with an information copy toappropriate O&M activities. Requests will contain thetechnical justification for the waiver and the proposedinterim standard for the equipment. DCA areas willreview the technical data and proposed and whereappropriate grant the waiver. If necessary, full resolu-tion of the waiver request will be carried to the Direc-tor, DCA.

a. Application. These standards apply to out-of-service testing performed at the TCF patch bay. Tech

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nical Control Facilities should determine distortionthresholds for the particular equipment and circuitswith their station and forward recommendations toappropriate DCA field activities for concurrence, withan information copy to appropriate Operation andMaintenance activities. When distortion thresholdsare exceeded, the technical controller will initiate cor-rective action to remove the equipment from service.For example, when the maximum output distortion al-lowed on a transmitter-distributor (out-of-service) is 1percent, corrective action will be initiated when theoutput distortion exceeds 4 percent. Corrective actionmay include changing transmitter-distributors, repair-ing equipment on line, or using a spare circuit.

b. Equipment Capability. If the design capability ofequipment listed in subsequent paragraphs permitsoperation at maximum distortion limits lower thanthose specified, the maximum limits specified in thetechnical manual or manufacturer handbook willapply.

c. VFCT. With the transmit and receive terminalsconnected back-to-back, sending and receiving loopsproperly terminated, and all transmit tones at properlevels, random undistorted signals will be keyed simul-taneously into each sending loop at the maximummodulation rate of the terminal design. The maximumdistortion measured in the receiving loops will notexceed 4 percent total peak telegraph distortion atmodulation rates up to and including 75 baud.

d. Transmitting Equipment Output Distortion. Theoutput distortion (all types) of electromechanical, elec-tronic, or composite transmitting devices (eithersequential or coincidental selection) will not exceed.one percent.

e. Electromechanical Receiving Devices. Electrome-chanical receiving devices shall be capable of tolerat-ing signal distortion as follows:

(1) Total peak distortion:45 percent.(2) Bias distortion: 45 percent.(3) End distortion: 45 percent.(4) Cyclic distortion 22.5 percent.

f. Electronic-Input Receiving Devices. Receiving devices utilizing electronic input circuitry shall becapable of tolerating signal distortion as follows:

(1) Total peak distortion: 49 percent.(2) Bias distortion: 49 percent.(3) End distortion: 49 percent.(4) Cyclic distortion: 24.5 percent.

g. Electromechanical Polar Relays. Total distortionintroduced into the transmission facilities, attributa-ble to the relay, shall be less than two percent.

h. Electronic Polar Relays. Total distortion introduced into transmission facilities, attributable to therelay, shall be less than one percent.

i. Differential Phase Shift Keying (DPSK) Modems.DPSK modems &all operate in accordance with per

4-38

formance requirements when the isochronous distor-tion of the input data is less than or equal to 10percent measured at the data signaling rate of themodem. The isochronous distortion of the output datasignal when measured at the operating data signalingrate shall be less than four percent.

j. Digital Regenerative Repeaters.(1) Synchronous repeater input will accept the fol-

lowing distortion limits and provide an output signalwith not more than three percent distortion, of whichnot more than one-third (one percent) is bias:

(a) Total peak distortion: 49 percent.(b) Bias distortion: 49 percent.(C) Cyclic distortion: 49 percent.(d) Fortuitous distortion: 49 percent.

(2) Start-stop repeater input will accept thefollowing distortion limits and provide an outputsignal with not more than three percent distortion, orwhich not more than one-third (one percent) is bias:

(a) Total peak distortion: 49 percent.(b) Bias distortion: 49 percent.(c) Cyclic distortion: 24.5 percent.(d) Fortuitous distortion: 24.5 percent.

k. Punched Card Readers. Punched card readerswill produce not more than one percent distortion ofthe signal element for electronic devices and 3.5percent distortion for electromechanical devices, asmeasured in relation to the theoretically correct unitinterval duration.

l. Card Punch. The card punch will operate withouterror if the input distortion is less than the following:

(1) Total peak distortion: 49 percent.(2) Bias distortion: 49 percent.(3) End distortion: 49 percent.(4) Cyclic distortion: 24.5 percent.

m. Magnetic Tape Readers. Total distortion attrib-utable to the magnetic tape reader will not exceed onepercent at the output of the intermediate equipment.

n. Magnetic Tape Recorders. Magnetic tape re-corders will operate without error if the input distor-tion is less than the following:

(1) Total peak distortion: 49 percent.(2) Bias distortion: 49 percent.(3) End distortion: 49 percent.(4) Cyclic distortion: 24.5 percent.

o. Paper Tape Readers.(1) Electromechanical Equipment. The total out-

put distortion will not exceed one percent for thestandard 5-unit code character interval, and 3.5 per-cent for the standard 8-unit code character (ASCII).

(2) Equipment Incorporating Electronic OutputCircuitry. The total output distortion will not exceedone percent.

p. Paper Tape Punches. Electromechanical papertape punches incorporating electronic serial input cir

cuitry will operate without error if the input distortionis less than the following:

(1) Total peak distortion: 49 percent.(2) Bias distortion: 49 percent.(3) End distortion: 24.5 percent.

q. Link Encryption Equipment. Link encryptionequipment will accept distortion (all types) up to 49percent and provide an output signal with not morethan one percent distortion.

4-43 . Conduc t o f Tes t s

The Circuit Control Office designated in the TSO is re-sponsible for circuit activation, to include the schedul-ing, supervising, and reporting of circuit tests. TheCCO will ensure that each segment of the circuit isproperly aligned and tested against the applicablestandards prior to conducting end-to-end testing.Intermediate TCF's on the circuit path will beresponsive to directions issued by the CCO.

a. End-to-end testing, as used in this technicalmanual refer to the point nearest the user terminals ateach end of the circuit where the capability exists toperformance required testing. In many cases, this will bethe serving TCF or PTF. In some cases, end-to-endtesting may be performed at the user terminal. Tech-nical Control Facilities will determine the point atwhich required end-to-end test measurements aremade for each circuit. When tail segments between theTCF and the user cannot be readily tested on a sched-uled basis, arrangements will be made to test the userloop from the TCF to determine loop characteristics.Data obtained from this test will be retained in theTCF for reference during subsequent Quality Controltesting or troubleshooting.

b. Leased circuits are considered to be one segment,regardless of the number of breakout points in the cir-cuit. Common carriers are responsible for providing re-quired signals at the point where government andcommercial facilities interface.

4-44 . Tes t Repor t ing

a. The CCO will submit an In-Effect Report orException Report as specified in establishedprocedures. The following instructions pertain to submission of the reports:

(1) Subsequent to submitting an In-Effect Report,the Circuit Parameter Test Report, DD Form 1697 willbe forwarded in accordance with existing directives to

TM 11-5895-1012-10

the DCA activity that issued the TSO and the cogni-zant DCA region.

(2) When an exception report must be submitted,the CCO will include in the message, as a part of thestatement of the problem, an extract of the appropri-ate portion of the Circuit Parameter Test Report.These extracts will include identification of the testthat failed to meet specifications, specific measure-ments obtained and comments, e.g., change in audiofrequency + 20 Hz, measurement made at stationAlpha from station Bravo (include further commentson nature of trouble and estimated time to repair).

b. When it is determined as a result of out-of-serviceQuality Control testing that circuit or equipmentparameters cannot be brought within test and ac-ceptance specifications, the CCO or affected TechnicalControl Facility will forward the following informa-tion to appropriate DCA and operation and main-tenance elements. DCA, in cooperation with lateralO&M elements, will ensure that required technicalassistance is provided to return the circuit or equip-ment test and acceptance specifications.

(1) Identification of circuit or equipment.(2) Test and acceptance measurements for those

parameters failing to meet specifications.(3) Out-of-service Quality Control test measure

ments for those parameters failing to meet specifica-tions.

(4) Remarks.

4-45. Recording Test Results

a. DD Form 1697 (Circuit Parameter Test Report)will be used to record the results of testing performedfor initial acceptance of service and for each re-configuration of the circuit. A copy of this test reportwill be filed with the corresponding TSO at thecognizant DCA region or area and maintained in theTechnical Control Facility files. DD Form 1697 may beoverprinted as required by DCS operating elements.

b. DD Form 1697 will not be forwarded to DCA oroperation and maintenance elements when scheduledor unscheduled quality control testing is performedunless tasked to do so for specific circuits and forspecific periods of time. However, a record of qualitycontrol tests and test results will be maintained in theTechnical Control Facility files. Local forms may beused provided they contain all information requiredfor DD Form 1697.

Section VI. CIRCUIT PERFORMANCE AND QUALITY CONTROL TESTING4-46. Introduction

by detecting and correcting adverse trends before thea. Effective worldwide service to all users of the user service is affected.

DCS requires each segment of the system to be op- b. Quality control is that function by which per-erated and maintained at its specified operating level. formance is measured and the results are then com-The concept of quality control and performance pared against established standards. Optimummonitoring is to prevent interruption to user service performance can be achieved and maintained by

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thorough testing and analysis of test results. An effec-tive quality control program consists of schedulingprescribed tests, measuring specific parameters, com-paring recorded measurements against applicablestandards, trend analysis and directing corrective ac-tions where indicated.

4-47. Quality Control of Government-o w n e d C i r c u i t s

a. In-Service Quality Control Testing. In-servicequality control testing is performed regularly on allactive circuits within the Technical Control Facility.Measurements are made using high impedance bridg-ing to prevent interruption of user service. Normaluser traffic signals, telephone supervisory parameterswhich can be measured without interruption of serviceand then compared to levels normally found at thetransmission level point of the circuit under test.

(1) The technical controller analyzes the test re-sults to determine if corrective action is required tobring the circuit within system standards or theoriginal circuit acceptance parameters. When re-quired, corrective action can be accomplished byrerouting the circuit, equipment substitution on thenormal path, or, when neither is possible, obtaining auser release of service in order to take the circuit outof-service for maintenance action.

(2) If the user does not want to release the circuitbecause of traffic load or mission requirements andstates that the degraded circuit is providing satisfac-tory service, the technical controller will make ar-rangements with the user for release of the circuit assoon as traffic conditions or mission requirementspermit.

(3) Appropriate maintenance elements and con-nected TCF's or PTF’s will be advised of the substand-ard condition of the circuit and of the projected down-time.

b. Out-of-Service Quality Control Testing. It is theresponsibility of the TCF designated as Circuit ControlOffice to schedule out-of-service quality control test-ing on all circuits over which responsibility has beenassigned. Periodic out-of-service testing permits end-to-end realignment of circuits to meet applicable DCScircuit parameters. Out-of-service testing usuallyrequires the user to release the circuit for a specifiedamount of time. Where at all possible a reroute will beprovided depending upon the circuit priority.

c. Communications Equipment. Scheduled qualitycontrol testing of all communications equipment supporting the DCS, including spares, is required. Com-munications equipment may be located in other sec-tions of the DCS Station; i.e. radio and carrier,automatic switching centers, communications centers,or within the TCF itself. In most cases, there is a Patchand Test Facility associated with the section involved.

All quality control testing of communications equipment will be conducted with the knowledge and per-mission of the TCF supervisor on duty. Operationalequipment will be tested off-line after the completionof regularly scheduled maintenance and in conjunctionwith the appropriate maintenance personnel. Wherepossible, equipment will be tested under maximumloading, such as all VFCT equipment channels beingkeyed with test messages. A review of trend analysisshould be made by TFC and maintenance personnelprior to the test. This will identify channels that havehad most of the outages and degree of maintenance ad-justments since the last scheduled test. This analysismay show the possibility of deteriorating componentsin the equipment and that this test period may requirea closer examination of the item of equipment than isnormally required during routing testing.

4 - 4 8 .

The basic requirement for quality control testing ofleased communications circuits is identical to that re-quired on Government owned circuits, with the follow-ing exceptions:

a In-Service Quality Control Testing. When it isdetermined through in-service testing that a circuitdoes not meet parameters contracted for in the Com-munications Service Authorization (CSA), one of thefollowing actions must be initiated:

(1) If the user states the circuit is not providingsatisfactory service, the circuit will be logged out-of-service with the commercial carrier for immediatecorrective action.

(2) If the user states that the circuit is providingsatisfactory service and the commercial carrier cannotprovide immediate corrective action or reroute, cor-rective action will be scheduled for a time mutuallyagreeable to the user and the carrier.

b. Out-of-Service Quality Control Testing. The Cir-cuit Control Office will coordinate quality control testschedules with commercial carriers to ensure that thecarriers will have personnel and *test equipment avail-able to participate in quality control tests and initiatecorrective actions if the circuit does not meetparameters contracted for in the CSA.

4-49. Quality Control

a. In-Service Test Schedules. Tests and frequency oftests shown in table 4-5 are considered the minimumrequired. Detailed schedules will be such that theseminimum requirements are satisfied. The TCF may in-crease the frequency of testing as necessary to ensurerequired operations. Test requirements may be satis-fied by use of automatic sensing equipment whichmeasure circuit parameters and provides a recordcopy of readings or alarms which sound when present

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exceeded. program will be used as the criteria for developing thervice Test Schedules. Out-of-service, quality control testing schedule. However, if deemed

end-to-end quality control tests, will be scheduled by necessary, the frequency of testing may be increasedthe responsible CCO. The tests and frequency of tests by the TCF to ensure optimum operating conditions.shown in table 4-5 are considered the minimum Quality control testing of equipment ensures that theessential. Selected out-of-service, end-to-end quality equipment meets the technical specifications con-control tests, as determined by the TCF, are required tained in the applicable technical manuals.after a transmission media failure, when equipment or d. Analysis of Test Results. Analysis of test resultslines are suspected of being faulty, when directed by and of equipment failures might indicate a need tothe appropriate DOCC or operation and maintenance revise test schedules. If a particular type of equipmentelement, or when deemed necessary by the TCF to or circuit is causing little or no outage between qualityensure optimum operation. control tests, an increase in the time interval between

c. Communications equipment Test Schedules. scheduled tests might be appropriate. Conversely, ifQuality control testing of operational and spare equip many outages are incurred or frequent adjustmentsment appearing on the TCF of PTF patch panels will are required on the equipment or circuit, a decrease inbe performed on a scheduled basis. The time interval the time interval between scheduled tests might be ap-currently used by the operation and maintenance ac- propriate.tivities in their established preventive maintenance

Table 4-5. Circuit Quality Control Schedule

Legend: 72-Every 72 Hours: Q-Quarterly; S-Semiannual: A-AnnualNote 1. V2 parameters will be used for out-of-service testing of spare unconditioned VF channels and circuits. unless otherwise specified.Note 2. Certain voice circuits utilize tone-on-while-idle supervisory signaling and will normally have a signal. either speech or tone. present

Measurements will be made at the monitor jack AS false rings will be caused by breaking the supervisory tone The normal speech level is - 12VU at the 0 dBm TLP. The normal tone-on-while-idle signal level IS - 20 dBm0

Note 3 Testing of channels under the PMP satisfies this requirementNote 4. Normal day-today technical control actions satisfy in-service test requirements for active dc circuits Spare dc circuits will be tested

for total peak distortion at least once every 72 hours. use of a spare dc circuit for reroute or establishing an on-call circuit satisfies this require-ment

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Table 4-6. Noise Power Conversion

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Table 4-6. Noise Power Conversion - Continued

4 - 5 0 . P e r f o r m a n c e M o n i t o r i n g

The DCS Performance Monitoring Program encom-passes monitoring the operation of the DCS transmis-sion links using critical operating parameters as per-formance indicators, and the analysis of the informa-tion received to develop performance trends. EachDCS Technical Control Facility will participate in thisprogram in accordance with established guidelines anddirectives.

4-51. Trend Analysis

Analysis of quality control data will be performed bythe Technical Control Facility on as near a real-timebasis as possible to identify degrading trends.

a. In-service quality control tests are the best toolsto identify degradation because measurements can betaken and recorded without interrupting the user.Measurements of each quality control test are com-pared with the measurements taken in the past. If adefinite change is noted, but the circuit is still provid-ing satisfactory user service, it should be flagged as aspecial interest circuit. One substandard measurement

does not constitute a trend. If, after several measure-ments are taken, further changes are indicated, a de-grading trend is evident and corrective action shouldbeinitiated.

b. Trend analysis is not limited to quality controlmeasurements. Trends can be detected from thenumber of outages over a given period of time. Theminimum number of outages per circuit, of course, isnot definable. The length of outage should not be con-sidered in this analysis.

c. Trend analysis can be expanded to determinewhether large number of outages are occurriug in thesame time frame. This analysis should be performed iflarge numbers of outages cannot be reduced after re-peated attempts to locate and correct the deficiency.

d. To simplify the analysis effort, data may betransposed from worksheets to a line or bar graph orsome other management tool, such as a computer run-off to give the history and present quality of a givencircuit or channel at a glance. Comparison with allother channels of a particular group will indicate thegeneral quality of the group.

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e. Figure 4-11 through 4-13 are examples oftypical graphs that may be used for trend analysis.

4 -52 . Excess ive S igna l Leve l s

Frequently, excessive signal levels are introduced intothe DCS from the user equipment. Excessive signal levelsfrom just a small number of users can cause crosstalkacross the baseboard of an entire system. Wheneverexcessive signal levels are detected, as a result of in-service quality control testing or as a result of a usercomplaint, immediate action will be initiated by thetechnical controller to locate the source. The servingTCF will immediately notify the violating user, directhis attention to the provisions of established direc-tives, and request that immediate action be taken tocorrect the deficiency. If the user continues to violatesignal level limits, the serving TCF will deny service to

the user until proper signal levels are by theuser. Actions of this nature will be properly docu-mented and immediately reported to the appropriateDocc and operation and maintenance activities.Denial of service for this reason should be donejudiciously and then only with approval of theTechnical Control Facility shift supervisor. As a ruleof thumb, the following criteria may be applied:

a. If the signal level is within 3 dB of the correctlevel, the serving TCF should initiate normal coordina-tion to correct the level.

b. If the signal level is between 3 dB and 6 dB abovethe correct level, the user must correct the level within15 minutes or the TCF will deny service.

c. If the signal level is more than 6 dB above the cor-rect level, the TCF will immediately deny service untilthe user provides the correct level.

Figure 4-11. Sample distortion trend analysis chart.

Figure 4-12. Sample noise level trend analysis chart. E L 3 Z 0 0 4 8

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Figure 4-13. Sample number of outages trend analysis chart.

4-53. Improper Termination of Circuits

Circuits improperly terminated and user terminalsmodified without appropriate Technical Service Orderaction will be denied access to the DCS, in accordancewith the procedures in paragraph 4-52. Access will bedenied the violating user until the terminations are inaccordance with the TSO. It is the responsibility of theuser to provide proper interface or terminations forcircuits entering the DCS.

4-54. Quality Control and PerformanceM o n i t o r i n g M a n a g e m e n t

monitoring is theresponsibility of each technical controller within the

. The technical control shift supervisor is responsi-ble for ensuring that scheduled testing is performed.The shift supervisor will advise the technical controlchief of any problem areas, and of any circuits of sys-

tolerance, and coordination with commercial carrierswhen leased circuits are out of tolerance.

b. The teat equipment on site is the responsibility ofthe Military Department operating the DCS Station.When an item of test equipment is inoperative orturned in for recalibration, and a like piece of equipment is not available, the test equipment should he de-clared “mission essential” and an attempt made toobtain a replacement so that fault isolation, qualitycontrol testing, and performance monitoring functionsare not impaired.

c. The DCS Station will prepare quality control andperformance monitoring checklists that enable anytechnical controller to test any equipment, circuit, orsystem within the facility.

4-55 . Qua l i ty Con t ro l Tes t s

Typical Quality Control Test procedures, with test set-up diagrams are contained in chapter 6. The testprocedures are general in nature and do not specifytest equipment by commercial type number of militarynomenclature. Test equipment is referred to in ageneric sense, i.e., level meter, signal source(generator), phase jitter meter, etc. Substitution of thespecific item of test equipment on site, shouldany technical controller to perform the specified Qual-ity Control tests.

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Section VII. IMPLEMENTATION OF COMMUNICATIONS SERVICES REQUIREMENTSAND INSTATION TESTING

4-56. Telecommunications Service Or-ders (TSO's)

The basic circuit design information for all new orchanged circuits is provided in the DCA Telecommun-ications Service Orders (TSO's). The TSO is the author-ization for DCA Headquarters of a DCA area toactivate, change, or deactivate circuits or trunks, toamend previously issued TSO’s, and to effect ad-ministrative changes. The TSO gives the following in-formation:

a. Issuing office.b. The year it is issued.c. TSO serial number.d. Circuit identification.e. The sequential action being taken on the circuit.

4-57 . TCF Respons ib i l i t i e s

a. The many variations found in the configurationsof DCS Station Technical Control Facilities preventthe development of precise procedures for the installa-tion, alignment, and testing of circuits which wouldapply to all types of circuits and to every DCS Station.However, there are certain functional steps in activat-ing circuits which are common to all stations. Upon re-ceipt of a TSO, the following steps are necessary toinstall, align, and test the circuit.

(1) Administrative processing and logging ofreceipt of the TSO.

(2) Preparation of the detailed in-station layoutdesignating specific cross-connects and specific equip-ment to be utilized as required by the TSO.

(3) Preparation of work order, or instructions, tosection(s) or personnel responsible for performing in-station wiring.

(4) Performance of in-station wiring check byTechnical Control Facility personnel on in-station cir-cuitry and associated transmission links in conjunctionwith adjacent TCF’s.

(5) Notification to appropriate control offices thatin-station and adjacent link tests are complete andmeet required criteria.

(6) Performance of circuit alignment tests by TCFpersonnel on in-station circuitry and associated trans-mission links in conjunction with adjacent TCF.

(7) Participation in end-to-end testing and di-rected by the appropriate control office.

(6) Administrative recording and reporting ofaction required or completed in conjunction with theinstallation. Managerial procedures for accomplishingthe above functions are left to the discretion of theindividual station. However, close coordination is im-portant between the section preparing the in-station

wiring layout and the Technical Controller perform-ing the in-station tests to prevent errors in the circuitinstallation and to ensure that required technicalparameters have been met.

b. Upon completion of the in-station installation,the Technical Controller is responsible for ensuringproper alignment of the in-station portion of the cir-cuit as well as the adjacent link(s). Continuity andtransmission level adjustments on the in-stationinstallation will be performed first. When the in-sta-tion portion of the circuit is properly installed and ad-justed, the input and output levels on all externaltransmission channels assigned to the circuit must headjusted to the proper value. Additional checks as re-quired to ensure proper functioning of conditioningand signaling equipment will be made. When theinternal and external alignment and checks are com-plete, an overall recheck of the complete installationwill be made. In the specific cases where a PTF is lo-cated between the Technical Control Facility and theuser, the TCF is responsible for ensuring that thetransmission levels, signaling and conditioning of thecircuit are properly adjusted between the user and thePTF.

c. Each circuit installed in the DCS will be tested inaccordance with the criteria specified in the DCS Tech-nical Schedule for the type of circuit in the TSO. Uponnotification from all intermediate TCF's that in-sta-tion and adjacent segment tests are complete, theTech&al Control Facility designated as Circuit Con-trol Office will initiate end-to-end tests of the circuit.Each of the specific tests are required to ensure com-pliance with the DCS circuit technical scheduleparameters. Refer to applicable DCA documentationto determine the DCS Technical Schedule and CircuitParameters for the circuit that has been installed.

d. The Technical Control Facilities concerned willimmediately notify the CCO or the ICO, when, for anyreason, delays are encountered or anticipated inactivation of circuits. The notification will contain detailed information on reasons for delay or inability toactivate circuits. Pertinent recommendations onmethods of providing service should also be included.This information may be used by the CCO in prepara-tion of an exception report.

e. Deactivation of circuits will be accomplishedafter coordination with all concerned and records willbe retained in an inactive or “dead” file for 6 monthsbefore destruction or disposition in accordance withestablishedrequirements.

f. Completion of activation records and reports isthe responsibility of the Technical Controller.

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4-58. Procedures for Changing andBui ld ing Ci rcu i t s

a , actions necessary to change a circuitare:

(1) Patch around the in-house portion of the exist-ing circuit, or terminate the circuit legs on the line sideof the patch panels with 600-ohm terminating plugs.

(2) Remove from the universal conditioningequipment shelf the modules of the string to be

(3) Remove cross-connects and rewire the IDF inthe conditioning equipment bay to form the desiredstring.

(4) Change cross-connections on the voice fre-quency, combined distribution frame (CDF) to obtainthe desired jack appearances and multiples, cable, orVFCT assignments necessary.

(5) Replace the conditioning modules.(6) Perform the necessary in-house quality control

checks (refer to chapter 6).(7) Remove patches or plugs installed in (1) above.(8) Perform the necessary station-to-station tests

(refer to chapter 6).b. Generally, actions necessary to build a new cir-

cuit are:(1) Form the desired conditioning equipment

string by cross-connecting at the IDF above the bay.(2) Cross-connect at the VF CDF to connect the

string to the desired patch panels (insert dummy plugsin all line jacks if the patch panels are already wired toa multiplex or channel VFCT, or cable pair).

(3) Plug in all conditioning equipment modules.(4) Perform the necessary in-house quality control

checks (refer to chapter 6).(5) Cross-connect the patch panels to the appro-

priate multiplex or VFCT channel or cable pair at theVF CDF (or remove dummy plugs if previously wired).-

(6) Perform the necessary out-of-service station-to-station quality control tests (refer to chapter 6).

4-59 . Sample C i rcu i t Bu i ld ing Procedure

The sample process for building voice frequency cir-cuit configuration figure 4-14 is as follows:

a Voice Frequency Circuit Connections. Refer tothe cut-sheet table 4-7 and figure 4-14 which illus-trate the following cross connection procedure.

(1) Connect the Equ Out (Drop) side of the receiveequal level patch panel circuit terminated on blockH17J, row 1, pins 3 and 4 to the signaling frequency(SF) unit receive input (line aide) terminated at bay 4.1on block TB3, row 1 pins E and F by cross-connectingblack H17J, row 1, pins 3 and 4 to block V9F, row 2,pins 1 and 2 respectively and at bay 4.1, TB3, row 1,pins E and F to TB9, row 1, pins E and F respectively.

(2) Connect the Equ In (Drop) side of the transmitequal level patch panel circuit terminated on block

H17K, row 1, pins 3 and 4 to the DF unit transmit out-put (line side) terminated at bay 4.1 on block TB3, row1 pins C and D by cross-connecting block H17K, row 1,pins 3 and 4 to block V9F, row 1, pins 3 and 4respectively and at bay 4.1, TB3, row 1 pins C and D toTB9, row 1, pins C and D respectively.

(3) Connect the SF unit receive output (Drop) sideterminated at bay 4.1 on TB3, row 1, pins H and J tothe amplifier (Al) input terminated at bay 4.1 on TB3,row 2, pins A and B by cross-connecting TB3, row 1,pins H and J to TB3, row 2, pins A and B respectively.

(4) Connect the SF unit transmit input (Drop) sideterminated on TB3, row 1, pins A and B to the Pad(P2) output terminated on TB3, row 3, pins H and 9 bycross-connecting TB3, row 1 pins A and B to TB3, row3, pins H and J respectively.

(5) Connect the SF unit E&M leads terminated atbay 4.1 on TB3, row 1, pins K and L to the ringdownconverter (RDC) E&M leads terminated at bay 4.1,TB3, row 1, pins K and L to TB3, row 6, pins K and Lrespectively.

(6) Connect the amplifier (Al) output terminatedat hay 4.1 on TB3, row 2, pins C and D to the pad (P1)input terminated at bay 4.1 on TB3, row 3, pins A andB by cross-connecting at bay 4.1, TB3, row 2, pins Cand D to TB3, row 3, pins A and B respectively.

(7) Connect the pad (P2) input terminated at hay4.1 on TB3, row 3, pins E and F to the amplifier (A2)output terminated at bay 4.1 on TB3, row 2, pins Hand J by cross-connecting at bay 4.1, TB3, row 3, pinsE and F to TB3, row 2, pins H and J respectively.

(8) Connect the pad (P1) output terminated at hay4.1 on TB3, row 3, pins C and D to the echo suppressorreceive input (line) terminated at bay 4.1 on TB3, row4, pins E and F by cross-connecting at bay 4.1, TB3row 3, pins C and D to TB3, row 4, pins E and F respec-tively .

(9) Connect the amplifier (A2) input terminated atbay 4.1 on TB3, row 2, pins E and F to the echo sup-pressor transmit output terminated at bay 4.1, TB3,row 4, pins C and D by cross-connecting at bay 4.1 onTB3, row 2, pins E and F to row 4, pins C and D respec-tively .

(10) Connect the echo suppressor receive outputterminated at bay 4.1 on TB3, row 4, pins H and J tothe 2/4 wire terminating set receive input terminatedat bay 4.1 on TB3, row 5, pins A and B by cross-con-necting at bay 4.1, TB3, row 4, pins H and J to row 5,pins A and B respectively.

(11) Connect the echo suppressor transmit inputterminated at bay 4.1 on TB3, row 4, pins A and B tothe 2/4 wire terminating set transmit output mi-nated at bay 4.1, on TB3, row 5, pins C and D by cross-connecting at bay 4.1 on TB3, row 4, pins A and B torow 5, pins C and D respectively.

(12) Connect the 2/4 -wire terminating set’s 2 wire

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line terminated at bay 4.1 on TB3, row 5, pins K and Lto the E&M/25 Hz ring down converter's Send In (T1,R1) line terminated at bay 4.1 on TB3. row 6, pins Aand B by cross-connecting at buy 4.1, TB3, row 5, pinsK and L, to TB3, row 6, pins A and B respectively.

(13) Connect the 2/4 wire terminating set termi-nated at bay 4.1 on block TB3, row 5, pins E and F tothe VF primary patch panel terminated on blockH13K, row 1, pins 3 and 4 by cross-connecting at bay4.1, TB3, row 5, pins 3 and F to TB9, row 5, pins E andF respectively and block V9F, row 10, pins 1 and 2 toblock H13K, row 1, pins 3 and 4 respectively.

(14) Connect the E&M/25 Hz ringdown converterReceive In line terminated at bay 4.1 on TB3, row 6,pins C and D to the VF primary patch panel equipmentside (T1, R1) terminated on block H13K, row 1, pins 3and 4 by cross-connecting at bay 4.1 TB3, row 6, pinsC and D to TB9, row 6, pins C and D respectively andblock H13K, row 1, pins 3 and 4 to block V9F, row 11,pins 3 and 4 respectively.

b. Voice Frequency Level Adjustments. The In-Station test will be run before connecting to the multi-plexer equipment. Adjust levels from the equal levelpatch panel to the primary patch panel as follows:

(1) At the equal level patch panel, the receive andtransmit levels will be at 0 dBm.

(2) The SF-2600 has approximately 0 dB inser-tion loss and will not affect the circuit level.

(3) Adjust amplifiers 1 and 2 for a 12 dB gain andpads 1 and 2 for an 8 dB loss to compensate for the 4dB insertion loss of the 4 wire termination set and al-low an operation level of 0 dBm at the voice frequency

(4) The E&M/25 Hz converter and echo suhas approximately 0 dB insertion loss and will not af-fect the circuit levels.

c. In-Station Testing After the correct circuit levelshave been obtained, perform the in-station test proce-dures contained in chapter 6. To use a test on a 2 wirecircuit, use the same two-wire circuit for both transmitand receive tests and omit the terminating resistorwhen necessary.

d. Multiplexer Equipment Connections. Refer tothe sample cutsheet (table 4-7) and cross-connect asfollows:

(1) Connect the multiplexer receive circuit termi-nated on block V32K, row 1, pins 3 and 4 to the equallevel patch panel DEM IN (line) terminated on blockH17J, row 1, pins 1 and 2 by cross-connecting blockV32K, row 1, pins 3 and 4 to block H17J, row 1, pins 1and 2 respectively.

(2) Connect the multiplexer transmit circuitterminated on block V32K, row 1, pins 1 and 2 to theequal level patch panel MOD OUT (Line) terminatedon block H17K, row 1, pins 1 and 2 by cross-connect-ing block V32K, row 1, pins 1 and 2 to block H17J,row 1, pins 1 and 2.

c. Final Testing. Perform the out-of-service qualitycontrol (station-to-station) testing contained in chapter 6. If the circuit checks out in accordance with thetesting and conforms to established parameters, thenreport the circuit ready for operation in accordancewith established procedures.

Table 4-7. Sample cutsheet for 2-wire voice circuit t (25 Hz signaling and echo suppressor control)

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Table 4-7. Sample cutsheet for 2-wire voice circuit (25 Hz signaling and echo suppressor control) - Continued

Section VIII. ACCEPTABILITY OF NEW EQUIPMENT

4-60. General

There is a need for continuing improvement in trans-mission quality. Therefore, integration of new equipment into the DCS is accomplished in some areas ofthe world every week. Technical and operational com-patibility is always an important consideration.

4 - 6 1 . t e c h n i c a l C o n t r o l F a c i l i t y R e s p o n -s ib i l i t i e s

a. The Technical Control Facility chief will:(1) Supervise an evaluation test of the equipment

to be cutover before it is placed on-line for DCS traf-fic. This will include as a minimum, but not be limitedto, the following

(a) All quality control tests that are normallyperformed on the subject item of equipment.

(6) Back-to-back and looped tests will ‘be per-formed as appropriate.

(c) Preparation of quality control records for thenew equipment to include posting of all test informa-tion. A copy of the initial tests will be provided the ap-propriate DCA area or region.

(2) Coordinate with appropriate control officesand other DCS Stations, as required, the addition ofthe new equipment into the system.

(3) Supervise the cut-over of all circuits to the new

equipment.(4) Supervise the testing of all circuits that re-

quire conditioning to ensure that the proper transmis-sion parameters are maintained.

b. Special attention must be given to protection ofservice to users that have control, error detection, andalarm devices on their circuits. Full coordination mustbe made prior to any cut-over or testing to maintainoperations without damage to communications equipment.

c. Where service must be interrupted for cut-over ofnew equipment, the established procedures must befollowed. Cut-over plans will be submitted to the ap-propriate DOCC in sufficient time to review and coor-dinate the plan.

4 - 6 2 . Tes t and Accep tance

Acceptability of new systems and subsystems usuallyrequire the services of test and acceptance (T&A)teams. In some cases, one terminal and sometimesboth, may terminate in a facility where Technical Con-trol Facility personnel are not assigned, but where thefacility is aligned as a system or subsystem reportingresponsibility of a Technical Control Facility. In allcases it is imperative that personnel of that TechnicalControl Facility be members of the T&A teams accept

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Figure 4-141. SampleSample voice frequency circuit configuration connection diagram (sheet 1 of 3).

Figure 4-142. SampleSample voice frequency circuit configuration connection diagram (sheet 2 of 3)

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Figure 4-143. Sample voice frequency circuit configuration diagram (sheet 3 of 3).

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CHAPTER 5

S T A T I O N M A I N T E N A N C E

5 - 1 .

Operator's preventive maintenance is the systematiccare, servicing, and inspection of equipment to pre-vent the occurence of trouble, to reduce downtime,and to assure that the equipment is serviceable.

a Systematic Care. The procedures given in para-graphs 5-3, 6-4, 5-5, and 5-6 cover routine sys-tematic care and cleaning essential to proper upkeepand operation of the equipment. Item numbers in-dicate the sequence of minimum inspection require-ments.

b. Preventive Maintenance Checks and Services.The preventive maintenance checks and servicescharts (para 5-3 through 5-5) outline functions to beperformed at specific intervals. These checks and serv-ices are designed to maintain Army Equipment in acombat-serviceable condition; that is, in good general(physical) condition and in good operating condition.The charts indicate what to check, how to check, andthe normal conditions. Defects discovered duringoperation of the technical control facility will be notedfar future correction, to be made as soon as equipmentcan be freed from service. Operation will be stopped

immediately if a deficiency is noted which would dam-age the equipment. If the defect cannot be remedied bythe operator, higher category of maintenance or repairis required.

5 - 2 . P r e v e n t i v e M a i n t e n a n c e C h e c k s a n ds e r v i c e s P e r i o d s

Preventive maintenance checks and services of thetechnical control facility are required daily, weeklyand quarterly.

a Paragraph 5-3 specifies the checks and servicesthat must be performed every day that the equipmentis used, and under the special conditions listed below:

(1) When the equipment is initially installed.(2) When the equipment is reinstalled after

removal for any reason.(3) At least once a week, if the equipment is main-

tained in standby condition.b. Paragraph 5-4 specifies additional checks and

services that must be performed on a weekly basis.c. Paragraph 5-5 specifies other checks and services

that must be performed on a quarterly basis.

5-3. Operator Daily Preventive Maintenance Checks and Services

5-4. Operator Weekly Preventive Maintenance Checks and Services

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5 - 5 . O p e r a t o r Q u a r t e r l y P r e v e n t i v e M a i n t e n a n c e C h e c k s a n d S e r v i c e s

5 - 6 . C l e a n i n g

a. Materials Required. The following materials arerequired for cleaning the equipment in the technicalcontrol facility:

(1) Trichloroethane.(2) Soft, lint-free cloth.(3) Liquid detergent.(4) Nylon bristle brush.

WARNINGThe fumes of trichloroethane are toxic. Pro-vide thorough ventilation whenever used. DCNOT use near an open flame. Trichloroethaneis not flammable, but exposure of the fumesto an open flame or hot metal surface con-verts them to a highly toxic phosgene gas. In-halation of this gas could result in serious in-jury or death.

b. Methods. Perform the following procedures to

clean the equipment in the technical control facility:(1) Inspect exterior surfaces of the equipment for

dust, dirt, grease and fungus.(2) Remove the dust and loose dirt with a soft,

clean cloth.(3) Remove grease, fungus, and ground-in dirt

from metal parts with a cloth dampened (not wet) withtrichloroethane.

(4) Remove dust or dirt from plugs and jacks witha soft brush.

CAUTIONDo not press on the METER FACE whencleaning. Damage to the equipment may re-sult.(5) Clean the front panel, meter face, and controls

of the equipment using a soft, clean cloth. If necessary,dampen the cloth with water or mild detergent formore effective cleaning.

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TM 11-5895-1012-10

CHAPTER 6

TEST PROCEDURES

6 - 1 . I n t r o d u c t i o n

a. Scope of Testing. Test procedures in this chaptercover station to station (quality control) and in-station(maintenance) testing. However, testing at a particularfacility should not be limited to the testing describedby this chapter nor should all facilities necessarilyperform all the tests described in this chapter. Thenumber and types of tests performed at a specific tech-nical control facility depends on the type of serviceprovided by the facility and on the technical servicesschedule for that facility. The tests in this chapter areprimarily intended for checking multiplex voice-chan-nel breakout to multiplex voice-channel breakout linkswith single or multiple hop paths.

b. Quality Control Tests. Quality control or stationto station tests should be performed regularly as speci-fied in chapter 4. These tests are used for evaluation ofthe performance of a circuit and in end-to-end circuitfault isolation.

c. Maintenance Tests. Maintenance or in-stationtests should be performed prior to putting a circuitinto operation if the circuit has just been built or re-paired. They are also used in troubleshooting stationequipment.

6-2 . Desc r ip t ion o f Tes t Equ ipment

The test equipment described below is required toperform the tests specified by this chapter. Thedescriptions given are of a general nature since thetest equipment at each facility varies with the func-tions of that facility and the services it provides.

a. Noise Measuring Test Set. The noise measuringtest set is used to measure noise and signal levels to-85 dbm. It has a frequency range of 50 to 5000 Hzand may be balanced for either 600 or 900 ohmsimpedance. If a Universal Transmission MeasuringSystem is available, it may be used in place of the noisemeasuring test set.

b. Transmission Test Set. The transmission test seta test oscillator, an attenuator, a matching

and a level meter. It has the followingperformance characteristics:

(1) Minimum frequency range of 20 Hz to PO KHz(2) Frequency-Amplitude response of less than 0.5

db variation over 20 Hz to 10 KHz into a matchingresistive load.

(3) Minimum output level range of + 5 to -30dbm.

(4) Output impedance of 600 to 900 ohms,balanced.

(5) Input of level meter is 600 or 900 ohms.c. Envelope Delay Test Set. The envelope delay test

set consists of a transmitter and receiver. It measuressignal delay and amplitude versus frequency. It hasthe following performance characteristics:

(1) Carrier frequency adjustable from 200 Hz to600 Hz.

(2) Modulation frequencies of 25, 83 1/3, and 250Hz.

(3) Amplitude accuracy of ± 0.5 db.(4) Delay accuracy of ±25 microseconds at 25 Hz

or ± 2 microseconds at 250 Hz modulation.d. Frequency Counter. The frequency counter has a

range of 200 to 4000 Hz and a sensitivity of 100 milli-volts. It has an accuracy of ± 1 count.

e. Frequency Selective Voltmeter. The frequencyselective voltmeter operates in the range of 5 to 1600KHz with an accuracy of 0.5 db. It is sensitive from-90 to +30 dbm and has two bandwidths (250 or2500 Hz).

f. Impulse Noise Counter. The impulse noise count-er has three adjustable ranges and is capable of count-ing impulses above the three adjusted levels. It isequipped with a timer and a storage capacity of atleast four digits while counting up to 10 counts per sec-ond minimum.

g. Oscilloscope. The oscilloscope may be either asingle or a dual trace with a minimum rise time of 10microseconds or less.

h. Phase Jitter Meter. The phase jitter meter meas-ures the phase jitter of a single frequency signal. It hasa minimum level range of -30 to 0 dbm with a meas-uring range of at least 0 to 30 degrees peak to peak jit-ter. The readout is in degrees peak to peak jitter.

i. Dual-Channel Recorder. The dual-channelrecorder is capable of measuring 0.1 to 500 volts witha sensitivity of 0.1 volts per millimeter. The chartspeed is adjustable.

j. Signal Test Set. The signal test set measures pulsespeed and percent of break. The test set also generatespulses used to test signaling circuits and may be usedas a pulse repeater or converter.

k. Test Set, Teletypewriter AN/GGM-15(V)1. Thistest set provides a capability for measuring signals indc teleprinter/data loops and for transmitting digitaltest messages over these loops. The test set includes a

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TM 11-5895-1012-10

signal generator, a signal distortion analyzer, and anoscilloscope. These items are described below:

(1) Signal Generator SG-860/GGM-15(V). Thisunit generates data and telegraph signal outputs withcontrolled distortion at speeds up to 9600 baud. Var-ious message options are available for Baudot orADCII codes.

(2) Signal Distort ion Analyzer TS-2862/GGM-15(V). This unit performs three major func-tions: distortion analysis, distortion monitoring, anderror rate determination.

(3) Oscilloscope OS-20/GGM-15(V). This unit isused to display the signal under analysis.

l. Accessory Items. The accessory items listed beloware required for some of the tests in this chapter.

(1) Test Tone Source. 1000 Hz at - 10 dbm0.(2) Resistors. Two 300 ohm ± 1%, 1 watt resistors

and one 150 ohm ± 1% 1 watt resistor are required.(3) Transformer. An center-tapped audio trans-

former with a 1:1 ratio and an 600/600 ohm impe-dance is required.

6 - 3 . T e s t C o n d i t i o n s

a. Patch Panels. Unless otherwise specified, stationto station tests will utilize two equal level patch panelswhile in-station tests will utilize one equal level andone primary patch panel.

b. Service Conditions. Unless otherwise specified,the circuit to be tested will he out of service. However,it will be aligned and conditioned for the circuitcharacteristics and transmission levels specified in theapplicable TSO.

6 - 4 . I d l e C h a n n e l ( R e s i d u a l ) N o i s e T e s t(f ig. 6-1)

a. Purpose. This test will measure idle channel (resi-dual) noise on a circuit between stations or within astation and will determine circuit compliance withstandard operating requirements. Idle channel or resi-dual noise is a combination of all of the disturbancesoccurring within the channel bandwidth and includesnoise caused by nonlinearities, crosstalk, and thermaleffects.

b. Test Equipment. The following test equipment isrequired to perform this test:

(1) Noise Measuring Test Set.(2) Terminating plugs (600 ohms) and patch cords.

c. Station-to-Station Test. Contact distant stationand arrange for one station to act as transmitter andone as receiver. Perform the procedure below and thenreverse roles and repeat the procedure.

(1) Transmitting Circuit. If the local station is toact as transmitter, prepare the transmitting circuitshown in figure 6-1.

(2) Receiving Circuit. If the local station is to actas receiver, prepare the receiving circuit shown in fig-

ure 6-1.(3) Procedure. The receiving station will measure

and record the noise level indication. This measure-ment will be taken with the Noise Measuring Test Setset for C message filtering and will be measured indbrnc.

(4) Performance Standard. Refer to the TechnicalServices Schedules (table 4-2) for the maximum allow-able noise for the channel being tested. The noisemeasured during this test will not exceed the levelspecified by the Technical Services Schedule.

d. In-Station Test. In-station testing is accom-plished in the same manner as station to station test-ing except the local station acts as both transmitterand receiver.

6-5. Frequency Response Test (f ig. 6-2)

a. Purpose. This test will measure frequencyresponse of a circuit either between stations or withina station and determine circuit compliance with thestandard operating requirement. Frequency responseis the capability of a system or component to pass agroup of frequencies with the original amplitude rela-tionship relatively intact.

b. Test Equipment. The following test equipment isrequired to perform this test:

(1) Transmission Test Set.(2) Noise Measuring Test Set.(3) Terminating plugs (600 ohms) and patch cords.

c. Station-to-Station Test. Contact distant stationand arrange for one station to act as transmitter andone as receiver. When test has been completed reverseroles.

(1) Transmitting Circuit. If the local station is toact as transmitter, prepare the transmitting circuitshown in figure 6-2 and set the equipment as follows:

(a) Patch panel impedance selectors at 600ohms.

(b) Patch panel frequency control at less than 5KHZ

(c) Transmission Test Set for 1000 Hz, -10dbm0 output to the transmit circuit.

(2) Receiving Circuit. If the local station is to actas receiver, prepare the receiving circuit shown in fig-ure 6-2 and set the equipment as follows:

(a) Input selector set for 600 ohms.(b) Filter selector set for 15 Hz.(c) Sensitivity set for 0.

(3) Procedure. While the transmitting station var-ies the frequency and holds the input level constant,the receiving station will record level readings on theNoise Measuring Test Set for the following fre-quencies: 300 Hz, 400 Hz, 500 Hz, 600 HZ, 700 Hz, 800Hz, 1000 Hz, 1200 Hz, 1400 Hz, 1600 Hz, 1800 Hz,2000 Hz, 2200 Hz, 2400 Hz, 2600 Hz, and 3000 Hz

(4) Performance Standard. Maximum deviation

6-2

TM 11-5895-1012-10

Figure 6-1. Idle channel (residual) noise teat.

from 1000 Hz if - 2 + 6 db.d. In-Station Test. h-station testing is accom-

plished in the same manner as station-to-station test-ing except the local station acts as both transmitterand receiver.

6-6 . Enve lope De lay Dis to r t ion Tes t ( f ig .6 - 3 )

a. Purpose. This test will measure circuit delaydistortion of circuits between stations or within astation and determine compliance of circuits with thestandard operating requirements. Circuit delay distor-tion is the distortion caused by differing amounts ofdelay for each of the various frequencies comprisingthe intelligence carrying signal. This is tested by trans-mitting several narrow band modulation envelopesand measuring the difference between the longest en-velope delay and the shortest envelope delay. This dif-ference is called the envelope delay distortion.

b. Test Equipment. Two envelope delay test sets arerequired if the teat is to be conducted within a station.One envelope delay test set is required for each station

the test is to be conducted between two stations.c. Station-to-Station Test. Contact distant station

and arrange for one station to act as transmitter andone as receiver. Perform the procedure below and then

roles and repeat the procedure.(1) Transmitting Circuit. If the local station is to

act as transmitter, prepare the transmitting circuit shown in figure 6-3 and set the envelope delay test set

as follows:(a) Transmit and receive reference.(b) Signal level of - 10 db.(c) Carrier frequency of 2000 Hz.(d) Modulation frequency of 25 Hz.

(2) Receiving Circuit. If the local station is to actas receiver, prepare the receiving circuit shown in fig-ure 6-3 and set the envelope delay test set as follows:

(a) Receive-return reference.(6) Carrier frequency of 2000 Hz.(c) Modulation frequency of 25 Hz.

(3) Procedure. With the transmitting stationenvelope delay test set set for the reference frequencyof 2000 Hz, record the delay indicated on the envelopedelay test set. The transmitting station will then setthe envelope delay test set for each of the frequencies.indicated in table 6-1. As each frequency is obtained,measure the delay and calculate the difference be-tween that delay and the delay measured at the refer-ence frequency of 2000 Hx. This difference may beeither positive (more delay than was measured at 2000Hz) or negative (less delay than was measured at 2000Hz).

(4) Performance Standard. The maximumdeviation permissible from the reference frequency of2000 Hz is indicated in table 6-1.

d. In-Station Test. In-station testing is accom-plished in the same manner as station to station testing except the local station acts as both transmitterand receiver.

6-3

TM 11-5895-1012-10

Figure 6-2. Frequency response test.

6 - 4

TM 11-5895-1012-10

Figure 6-3. Envelope delay distortion test.

6-5

TM 11-5895-1012-10

Table 6-1. Envelope Delay Measurements

6 - 8 . M i n i m u m L o n g i t u d i n a l B a l a n c e T e s t

6-7 . Aud io Frequency Tes t

a. Purpose. This test will measure maximum circuitfrequency change between stations or within a stationand determine compliance of circuits with the stand-ard operating requirements.

b. Test Equipment. The following test equipment isrequired to perform this test:

(1) Noise Measuring Test Set.(2) Frequency Counter (two required for in-station

test).(3) Terminating plugs (600 ohms) and patch cords.

c. Station-to-Station Teat. Contact distant stationand arrange for one station to act as transmitter andone as receiver. Perform the procedure below and thenreverse roles and repeat the procedure.

(1) Transmitting Circuit. If the local station is toact as transmitter, prepare the transmitting circuitshown in figure 6-4 and set the equipment as follows:

(a) 1000 Hz Test Tone Source set for - 10 dbm0coupled to transmit line.

(b) Frequency Counter set to measure ac within.1 Hz

(2) Receiving Circuit. If the local station is to actas receiver, prepare the receiving circuit shown infigure 6-4 and set the equipment as follows:

(a) Frequency Counter set to measure ac within.1 Hz.

(b) Noise Measuring Test Set set Hi Pass filter-ing and 600 ohm input.

(3) Procedure. The transmitting station willmeasure the Test Tone Source and record theindication to the nearest .1 Hz. The receiving stationwill measure and record the level meter indication onthe Noise Measuring Test Set. The receiving stationwill then observe the indication on the FrequencyMeter for one minute and record this measurement.The two stations will then compare the recorded fre-quencies and determine the difference between them.

(4) Performance Standard. The maximumpermissible change between the transmitted andreceived frequencies is ± 5 Hz.

d. In-Station Test. In-station testing is ac-complished in the same manner as station to stationtesting except the local station acts as both trans-mitter and receiver.

transmit and receive circuits and determine circuitcompliance with the standard operating requirements.Any voltage that causes a current to flow in the samedirection in both conductors of a circuit is alongitudinal voltage. This can be caused by extraneousvoltages induced into the circuit by either electro-magnetic or capacitive coupling to both conductorsfrom other circuits, or as a result of any externalelectrical disturbances. This test measuresof the induced longitudinal voltage on the signal volt-age by introducing a known signal voltage and measur-ing the resulting longitudinal voltage.

b. Test Equipment. The following test equipment isrequired to perform this test:

(1) Transmission Measuring Test Set (3 required).(2) Transformer, 1:1 ratio, 600/600 ohm, audio,

center-tapped.(3) Resistors, 300 ohm ± 1%, 1 watt (2 required).(4) Resistor, 150 ohm ± 1%. 1 watt.(5) Terminating plugs (600 ohms) and

c. Station-to-Station Input Teat. Costation and arrange for one station to act as trans-mitter and one as receiver. Perform the procedurebelow and then reverse roles and repeat the procedure.

(1) Transmitting Circuit. If the local station is toact as transmitter, prepare the transmitting circuitshown in figure 6-5 and set the equipment as fellows:

(a) Transmission test sets jumpered as shown infigure 6-5 with voltmeter function switch to on.

(b) Patch panel impedance selectors at 600ohms.

(c) Patch panel frequency selector at less than 5KHz.

(2) Receiving Circuit. If the local station is to actas receiver, prepare the receiving circuit shown infigure 6-5.

(3) Procedure.(a) At the transmitting station, set the fre-

quency of the Transmission Test Set No. 1 to a valuenear the top of the2700 Hz). Adjust theSet No. 1 for an inpumit input as read on Transmission Teat Set No. 3 volt-meter. Note the level in volts and label this V1.

(b) Adjust the range control ofTest Set No. 2 voltmeter for a suitable sensitivity,measure the low longitudinal signal across theohm resistor. Note this level and label it V2.

6 - 6

TM 11-5895-1012-10

Figure 6-4. Audio frequency test.

6 - 7

TM 11-5895-1012-10

(c) Remove the input signal by disconnectingTransmission Test Set No. 1 and observe TransmissionTest Set NO. 2 voltmeter. If the voltage measured byTransmission Test Set NO. 2 does not drop in valuewhen the input signal is disconnected, then the linenoise is probably mashing the reading Of V2. This con-&ion must be corrected before the test can be com-pleted.

(d) If the voltage measured by TransmissionTest Set NO. 2 (V2) did drop in value when the inputsignal was disconnected then calculate the Longi-tudinal Balance using the following formula:

Longitudinal Balance (db) = 20 Log10V1/V2.(4) Performance Standard. Minimum Longitu-

dinal Balance is 40 db.d. Station-to-Station Output Test. Contact distant

station and arrange for one station to act as trans-mitter and one as receiver. Perform the procedurebelow and then reverse roles and repeat the procedure.

(1) Transmitting Circuit. If the local station is toact as transmitter, prepare the transmitting circuitshown in figure 6-6 and set the equipment as follows:

(a) Transmission test set jumpered as shown infigure 6-6 with voltmeter function switch to on.

(b) Patch panel impedance selectors at 600ohms.

(c) Patch panel frequency selector at less than 5KHz.

(2) Receiving Circuit. If the local station is to actas receiver, prepare the receiving circuit shown infigure 6-6 and set the equipment as follows:

(a) Transmission test sets jumpered as shown infigure 6-6 with voltmeter function switches to on.

(b) Patch panel impedance selectors at 600ohms.

(c) Patch panel frequency selectors at less than5 KHz.

(3) Procedure.(a) At the transmitting station, set the fre-

quency of Transmission Test Set No. 1 to a value nearthe top of the audio bandwidth (approximately 2700Hz). Adjust transmission Test Set No. 1 for a level of- 10 dbm0 as read at the receiving station on Trans-mission Test Set No. 3 voltmeter. Note this level andlabel it V1.

(b) Adjust the range control of TransmissionTest Set No. 2 for a suitable sensitivity and measurethe voltage displayed on Transmission Test Set No. 2voltmeter. Note this voltage and label it V2.

(c) Calculate the longitudinal balance of the out-put circuit using the following formula:

Longitudinal Balance (db) = 20 Log10V1/V2.(4) Performance Standard. The permissable mini-

mum longitudinal balance is 40 db.e In-Station Testing, In-station testing is ac-

complished in the same manner as station to station

testing except the local station acts as both trans-mitter and receiver in both input and output tests.6-9 . S ing le Tone In te r fe rence Tes t

a. Purpose. This test will measure maximum singletone interference of circuits between stations orwithin a station and determine circuit compliance withthe standard operating requirements. These inter-ferring tones may come from carrier leak or fromnearby equipment or systems.

b. Test Equipment. Test equipment required to per-form this test consists of a Frequency Selective Voltmeter and terminating plugs (600 ohms) and patchcords.

c. Station-to-Station Test. Contact the distant sta-tion and arrange for one station to act as transmitterand one as receiver. Perform the procedure below andthen reverse roles and repeat the procedure.

(1) Transmitting Circuit. If the local station is toact as transmitter, prepare the transmitting circuitshown in figure 6-7.

(2) Receiving Circuit. If the local station is to actas receiver, prepare the receiving circuit shown infigure 6-7 and set the frequency selective voltmeter asfollows:

(a) Input impedance set for 600 ohms.(b) Input attenuator set so that the maximum

level of the single tone interference is included in themeasuring range of the voltmeter.

(3) Procedure.(a) Slowly sweep the frequency control of the

frequency selective voltmeter through the frequencyrange of the channel under test.

(b) Record the power level (in dbm) of the peaksindicated by the frequency selective voltmeter. Con-vert this measurement to dbm0 by allowing for therelative level of the transmission level point at whichthe measurement was made.

(c) Convert this level from dbm0 to dbm0 us-ing the conversion chart in figure 6-8. Read the fre-quency of the interferring tone from the frequencyselective voltmeter and then find the conversion factorfor the frequency in figure 6-8. Then, dbrnc0 = dbm0+ conversion factor.

(4) Performance Standard. Refer to the TechnicalServices Schedules (table 4-2) for the maximum allow-able noise for the channel being tested. The maximumsingle tone interference (measured in dbrnc0) will notexceed the level specified by the Technical ServicesSchedule.

d. In-Station Test. In-station testing is accom-plished in the same manner as station to station test-ing except the local station acts as both transmitterand receiver.6-10 . Impu l se No i se Tes t

a. Purpose. This test will measure impulse noise on

6 - 8

TM 11-5895-1012-10

Figure 6-5. Longitudinal balance input test.

6-9

TM 11-5895-1012-10

Figure 6-6. Longitudinal balance output test.

6-10

TM 11-5895-1012-10

Figure 6-7. Single tone interference test.

Figure 6-8. Conversion of dbm to dbrnc0.

6-11

TM 11-5895-1012-10

a circuit between stations or within a station and willdetermine circuit compliance with standard operatingrequirements. Impulse noise consists of transientwaveforms of various shapes, durations, and ampli-tudes. It can be caused by natural disturbances such aslightning or atmospheric static, or by manmade dis-turbances.

b. Test Equipment. The following test equipment isrequired to perform this test:

(1) Impulse Noise Counter.(2) Terminating plugs (600 ohms) and patch cords.

c. Station-to-Station Test. Contact distant stationand arrange for one station to act as transmitter andone as receiver. Perform the procedure below and thenreverse roles and repeat the procedure.

(1) Transmitting Circuit. If the local station is toact as transmitter, prepare the transmitting circuitshown in figure 6-9.

(2) Receiving Circuit. If the local station is to actas receiver, prepare the receiving circuit shown in fig-ure 6-9 and &the impulse noise counter as follows:

(a) Power switch to ON.(b) Hold switch to OFF.(c) Bridge/Term switch to Term.(d) Weighting selector to Voice.(e) Input impedance at 600 ohms.(f) Timing at 15 minutes.(g) Sensitivity controls set so that all impulse

hits above the reference level specified in the technicalschedules (table 4-2) will be registered or recorded.

(3) Procedure. Receiving station will record all im-pulse hits above the reference level specified in thetechnical schedules (table 4-2).

(4) Performance Standard. The maximum numberof impulse hits permissable in the 15 minute time pe-riod is 15.

d. In-Station Test. In-station testing is accom-plished in the same manner as station to station testing except the local station acts as both transmitterand receiver.

6-11. Terminal Impedance Test of Trans-mit Circuit (fig. 6-10)

a. h-pose. This test will measure the terminal im-pedance of the transmit circuit between stations orwithin a station and determine circuit compliance withthe standard operating requirement Terminal im-pedance must be kept within specifications to precludeimpedance mismatch which will result in poor fre-quency response, excessive loss of signal power, or im-proper signal level measurements

b. Test Equipment. The following test equipment isrequired to perform this test

(1) Transmission Test Set.(2) Terminating plugs (600 ohms) and patch cords.

c. Station-to-Station Test. Contact distant station

and arrange for one station to act as transmitter andone as receiver. Perform the procedure below and thenreverse roles and repeat the procedure.

(1) Receiving Circuit. If the local station is to actas receiver, prepare the receiving circuit shown in fig-ure 6-10.

(2) Transmitting Circuit. If the local station is toact as transmitter, prepare the transmitting circuitshown in figure 6-10 and set the equipment as fol-lows:

(a) Jumper the transmission test set as shown infigure 6-10.

(6) Set the transmission test set patch panel output impedance selector to 600 ohms.

(c) Set the transmission test set patch panel in-put impedance selector for bridging‘

(d) Set the transmission test set patch panel fre-quency selector at less than 5 KHz.

(e) Turn on the transmission test set voltmeter.(3) Procedure. Calibrate the transmission test set

for 1000 Hz and a 1 volt (V1) voltmeter reading.Switch the calibrate-measure switch back to the meas-ure position, and read the voltage (V2) on the trans-mission test set voltmeter. Calibrate the transmit im-pedance from the following expression:

V1 = transmission test set open circuit output voltageV2 = t-on teat set output voltage when termin-

ated at the receiving circuit.(4) Performance Standard. The permissable ter-

minal impedance is 600 ohms ± 10%.d. In-Station Test. In-station testing is accom-

plished in the same manner as station to station test-ing except the local station acts as both transmitterand receiver.

6-12. Terminal Im

the terminal im-pedance of the receive circuit between stations orwithin a station and determine circuit compliance withthe standard operating requirements. Terminal im-pedance must be kept with specifications to precludeimpedance mismatch which will result in poor fre-quency response, excessive loss of signal power, or im-proper signal level measurements.

b. Test Equipment. The following test equipment isrequired to perform this test:

(1) Transmission Test Sets (2 required).(2) Terminating plugs (600 ohms) and patch cords,

c. Station-to-Station Test. Contact distant stationand arrange for one station to act as transmitter andone as receiver. Perform the procedure below and thenreverse roles and repeat the procedure.

(1) Receiving Circuit. If the local station is to actas receiver, prepare the receiving circuit shown in fig

6-12

TM 11-5895-1012-10

Figure 6-9. Impulse noise test.

6-13

TM 11-5895-1012-10

Figure 6-10. Terminal impedance test for transmit circuit.

V2= receiving station voltage terminated in 600 ohmsure 6-11 and set the transmission test set as follows:(a) Jumpered as shown in figure 6-11.(b) Patch panel impedance selectors at 600

(4) Performance Standard. The permissable ter-minal impedance is 600 ohms ± 10%.

d. In-Station Test. In-station testing is accom-plished in the same manner as station to station test-ing except the local station acts as both transmitter

(c) Patch panel frequency selector at less than 5

(d) Voltmeter function switch to on.(2) Transmitting Circuit. If the local station is to

act as transmitter, prepare the transmitting circuitshown in figure 6-11 and set the transmission test setas follows:

6-13. Harmonic Distort ion Test (f ig. 6-12)

(a) Jumpered as shown in figure 6-11.(b) Patch panel input impedance selector at

bridging.(c) Patch panel frequency selector at less than 5

(d) Voltmeter function switch to on.(3) Procedure. The receiving station will calibrate

set for 1000 Hz and set it for 1on the transmitting station volt-

V1= receiving station open circuit voltage

measures the signal frequency and eachseparately and then gives a mathematicalfor computing the total harmonic distortion.

b. Test Equipment. The following test equirequired to perform this test:

(1) Transmission Test Set.(2) Frequency Selective Voltmeter.(3) Terminating plugs (600 ohms) and patch

c. Station-to-Station Test. Contact distantand arrange for one station to act as transmitter andone as receiver. Perform the procedure below and thereverse roles and repeat the procedure.

(1) Transmitting Circuit. If the local station is to

6-14

TM 11-5895-1012-10

Figure 6-11. Terminal impedance test for receive circuit.

act as transmitter, prepare the transmitting circuitwn in figure 6-12 and set transmission test set asws:

(a) Jumpered as shown in figure 6-12.(b) Patch panel impedance selectors at 600

ohms.

6-14. Composite Signal TransmissionLevel Test (f ig. 6-13)

(c) Patch panel frequency selector at less than 5KHz.

(d) Turn on voltmeter.(2) Receiving Circuit. If the local station is to act

as receiver, prepare the receiving circuit shown infigure 6-12 and set the frequency selective voltmeteras follows:

(a) Input impedance control at 600 ohms.(b) Bandwidth to 200 or 250 Hz.

(3) Procedure. Transmitting station will calibratethe transmission test set for a 700 Hz, - 10 dbm0 out-put. Receiving station will measure the circuit level of

the fundamental (700 Hz), second harmonic (1400 Hz),third harmonic (2100 Hz), ad fourth harmonic (2800Hz). Calculate the total harmonic distortion using thefollowing expression:

(4) Performance Standard. The maximum permis-total harmonic distortion is -40 dbm0.

d. In-Station Test. In-station testing is ac-complished in the same manner as station to station

testing except the local station acts as both trans-mitter and receiver.

t of operating conditionsrather than a measurement of circuit parameters. Assuch, this test is not applicable as an in-station ormaintenance test.

b. Test Equipment. A noise measuring test set andpatch cords are required to perform this test.

c. Procedure. Prepare the test arrangement shownin figure 6-13 and set the noise measuring test set for600 ohms impedance and for bridging. Set the filterselector for high pass filtering. The circuit being testedshould be in service and the connection should be madeat the VF patch panel. Read and record the indicationson the noise measuring test set.

d. Performance Standard. The required compositelevel is the reference level minus 13 dbm0.

6-15. Phase Jitter Test Using Oscil-

a. Purpose. This test will measure phase jitter of acircuit between stations or within a station and deter-mine circuit compliance with minimum operatingrequirements. Phase jitter is the instantaneous de-viation from the average phase of the signal and maybe caused by channel induced phase noise or byadditive amplitude noise. Phase jitter may bemeasured using an oscilloscope or using a phase jittermeter. The procedure for measuring phase jitter usingan oscilloscope is given below. The procedure for

6-15

TM 11-5895-1012-10

6-16

TM 11-5895-1012-10

Figure 6-13. Composite signal transmission level test.itter using a phase jitter meter is6-16.

b. Test Equipment. The following test equipment isrequired to perform this test:

(1) Test Tone Source, 1000 Hz at - 10 dbm (2 re-quired).

(2) Oscilloscope.C. Station-to-Station Test. Contact distant station

and arrange for one station to act as transmitter andone as receiver. Perform the procedure below and thenreverse roles and repeat the procedure.

(1) Transmitting Circuit. If the local station is toact as transmitter, prepare the transmitting circuit

If the local station is to actreceiving circuit shown in

. At the receiving station, patch the

(4) Performance Standard. The maximumpermissable peak-to-peak phase jitter is 15 degrees.

d. In-Station Test. In-station tasting is ac-complished in the same manner as station to stationtesting except the local station acts as both trans-mitter and receiver.

6-16. Phase Jitter Test Using Phase JitterMeter (f ig. 6-15)

a Purpose. This test will measure phase jitter of acircuit between stations or within a station and deter-mine circuit compliance with minimum operatingrequirements. Phase jitter is the instantaneous de-viation from the average phase of the signal and maybe caused by channel induced phase noise or by ad-ditive amplitude noise. Phase jitter may be measuredby using a phase jitter meter or an oscilloscope.The procedure for use with a phase jitter meter isgiven below. The procedure for using an oscilloscope isgiven in paragraph 6-15.

b. Teat Equipment. The following test equipment isrequired to perform this test:

(1) T&Tone Source, 1000 Hz at - 10 dbm.(2) Phase Jitter Meter.

c. Station-to-Station Test. Contact distant stationand arrange for one station to act as transmitter andone as receiver. Perform the procedure below and thenreverse roles and repeat the procedure,

(1) Transmitting Circuit. If the local station is toact as transmitter, prepare the transmitting circuit

6 - 1 7

TM 11-5895-1012-10

Figure 6-14. Phase jitter testing using an oscilloscope

shown in figure 6-15.(2) Receiving Circuit. If the local station is to act

as receiver, prepare the receiving circuit shown infigure 6-15 and set the phase jitter meter as follows:

(a) Power switch on.(b) Impedance switch to 600 ohms.(c) Meter select switch to input level.

(3) Procedures. At the receiving station, verifythat the input level is between +10 dbm and -40dbm. Then switch the meter select switch to frequencyand verify that frequency lock has been achievedSwitch the meter select switch to 30° P-P JITTER andread the meter indication of peak-to-peak phase jitter.

(4) Performance Standard. The maximumpermissable peak-to-peak phase jitter is 15 degrees.

d. In-Station Test. In-station testing is ac-complished in the same manner as station to stationtesting except the local stations act as both trans-mitter and receiver.

6-17. Station to Station Signaling Test(fig. 6-16)

a. Purpose. This test determines signaling per-formance and compliance with the standard operatingrequirements.

NOTEPrior to performing this test, the circuit shallbe aligned and conditioned to the requiredcircuit characteristics and transmission levelsspecified in the TSO.

b. Teat Equipment. The following teat equipmentrequired to perform this test:

(1) Signal Test Sets (2 required).(2) Terminating plugs (600 ohms) and patch cord

c. Teat Procedure. Contact distant station and arange for one station to act as transmitter and one asreceiver. Prepare the circuit as shown in figure 6-16and perform the procedure below. Then reverse rolesand repeat the procedure.

(1) Place the controls of each signal test set asfollows:

(a) Send PPS selector to ON (10 PPS).(b) Function switch to Test L & D.(c) TWD-L, LINE (E) key switch to OFF HOOK(d) TWD-D key switch to Thru & Meas.

(2) With the off hook signals being sent on the Mlead at each station, the E lead at both ends should begrounded as indicated by the extinguishing of theLINE (E) lamps.

(3) At both stations, switch the signal test setTWD-L, LINE (E) key switch on Oon-hook signal being sent to the M lead at each end,the E lead at both stations should be open as indicatedby the LINE(E) lamp at both stations being lighted.

(4) At the transmitting station, place the signaltest set controls as follows:

(a) Test-Send key switch to Send Osc.(b) Meter circuit selector % Break Direct.(c) Receive selector to any position except Send

and Rec.

6-18

TM 11-5895-1012-10

Figure 6-15. Phase jitter testing using a phase jitter meter.

6-19

TM 11-5895-1012-10

(d) Send selector to E&M line (M = B&G).(e) Send PPS selector to 10.(f) Function selector to Send Off Hook for

calibrating and Send & Rec for sending.(5) At the receiving station, place the signal test

set controls as follows:(a) Meter Circuit to % Break Direct.(b) Receive selector to G&O(E).(c) Function selector to CAL MTR for

calibrating and Send & Rec for measuring.(6) The receiving station will calibrate the %

break meter for 0% with the transmitting station inthe off hook condition (Function selector to OFFHOOK).

(7) If SF signaling is being tested, the trans-mitting station will send continuous pulse streams asfollows:

Pulse Rate % Break10 PPS 4710 PPS 6712 PPS 4712 PPS

(8) If DX signaling is being tested, the trans-mitting station will send continuous pulse streams asfollows:

Pulse Rate % Break8 PPS 548 PPS 6212 PPS 5412 PPS

(9) The receiving station will measure the percentbreaks of the received pulses.

d. Performance Standards. For SF signaling thepercentage breaks recorded at the receiving stationwill be 57 ± 10%, irrespective of the pulse rate used.For DX signaling the breaks recorded atthe receiving station will be 58the pulse rate used.

6-18. In-Stat ion Signal ing

a Purpose This test determines operational signal-ing capability.

b. Test Equipment. The following test equipment isrequired to perform this test :

(1) Signal Test Set.(2) Signal Unit.(3) Circuit Termination Panel.(4) Terminating plug (600 ohms) and patch cords.

c. Test Procedure. To test the receive line of a cir-cuit, prepare the circuit shown in figure 6-17 and per-

If a 4 wire circuit is totransmit lines. If FM

on a separate pair, then connect thelead from the MISC PATCH panel to the voice circuiton the of the primary patch panel.

(1) signal test set as follows:(a) Send PPS selector to ON (10 PPS).(b) TWD-L, LINE (E) selector to Off-Hook.

(c) Function selector to Test L&D.(2) Switch the TWD-L, LINE (E) selector to the

ON HOOK position. The circuit termination panelshould ring.

(3) Switch the MISC PATCH lead from the RECto the XMIT line and terminate the REC line with atermination plug. Send a ring out from the circuittermination panel. The LINE (E) lamp should light.

6-19. Net Loss Variation Test (fig. 6-18)

a. Purpose. This test will measure maximum netloss variation between stations or within a station anddetermine circuit compliance with the standardoperating requirement.

b. Test Equipment. The following test equipment isrequired to perform this test:

(1) Transmission Test Set.(2) Noise Measuring Test Set.(3) Dual-Channel Recorder.(4) Termination plugs (600 ohms) and patch cords

c. Station-to-Station Test. Contact distant stationand arrange for one station to act as transmitter andone as receiver. Perform the procedure below and themreverse roles and repeat the procedure.

(1) Transmitting Circuit. If the local station is toact as transmit&, prepare the transmitting circuit infigure 6-18 and set the transmission test set asfollows:

(a) Patch panel output impedance selector to600 ohms.

(b) Frequency selector to less than S KHz.(c) Turn on voltmeter.

(2) Receiving Circuit. If the local station is to actas receiver, prepare the receiving circuit shown infigure 6-18 and set the noise measuring test set asfollows:

(a) Filter selector at Hi Pass.(b) Input at 600 ohms.(c) Sensitivity selectors initially at 0 dbm.(d) On the recorder, place the chart speed

selector to one inch per minute and the range selectorto 1 volt.

(3) Procedure.(a) The transmitting station will calibrate the

transmission test set for a 1000 Hz at - 10 dbm0 out-put signal.

(b) Using only the servo pm drive correspondingto the upper module, the receiving station will cali-brate the recorder to zero the servo pin in the center ofthe chart.

(c) The receiving station will record the level ofthe 1000 Hz signal for a period of 15 minutes between0800Z and 1200Z hours and for a period of 15 minutesbetween 2000Z and 2400Z hours. During this time, thetransmitting station will vary the output of the trans-mission test set in 1 db steps, and the receiving station

6-20

TM 11-5895-1012-10

Figure 6-16. Station to station signaling teat.

6-21

TM 11-5895-1012-10

Figure 6-17. In-station signaling test.

will verify that the level meter changes in 1 db steps d. In-Station Test. In-station testing is ac-and the strip chart recorder shifts the distance in steps complished in the same manner as station to station

testing except the local station acts as both trans-S tandard . The maximum mitter and receiver.

is ± 4db.

6-22

Figure 6-18. Net loss variation test.

TM 11-5895-1012-10

6 - 2 0 . T o t a l P e a k a n d A v e r a g e B i a s T e l e -g r a p h D i s t o r t i o n T e s t

WARNINGDANGEROUS VOLTAGES are present dur-

ing the preparation of the test circuits speci-fied in figures 6-19 and 6-20. Turn all power

switches off before constructing these testcircuits. Failure to observe safety precautionscould result in serious injury or death.

c. Station-to-Station Test. Contact distant stationand arrange for one station to act as transmitter and

as a receiver. Perform the procedure below and thenreverse roles and repeat the procedure.

(1) Transmitting Circuit. If the local station is toact as transmitter, prepare the transmitting circuitshown in figure 6-19 and set the AN/GGM-15(V)1test pattern generator controls as follows:

(a) Use DATAOUTPUT.(b) P-N switch to P.(c) DISTORTION SELECT to NO DIST.(d) LEVEL CODE to 5.(e) CHARACTER LENGTH to 7.(f) MESSAGE SELECT to MSG.(g) BAUD RATE to 75.

(2) Receiving Circuit. If the local station is to actas receiver, prepare the receiving circuit shown in fig-

(e) INPUT SELECT SWITCH to BRIDGINGH1Z.

(f) BAUD RATESELECTOR to 75.(g) DISTORTION SELECT to TOTAL PEAK.(h) TRANSITION SELECT to ALL.(i) ALARM switch to RESET.

(3) Procedure.(a) Turn on the power. If the distant station dis-

tortion analyzer signal lamp does not light, reverse thepolarity switch. At the transmitting station, transmitthe message "Quick Brown Fox".

(b) At the receiving station, read the total peakdistortion in percent and record it. The place the dis-tortion analyzer ALARM switch to RESET and theDISTORTION SELECTOR to AVERAGE S/M.

(c) At the transmitting station, transmit themessage "Quick Brown Fox". The receiving station willmad the average displacement of the mark-to-spacetransitions of the input signal as indicated on the per-cent distortion meter. If the mark indicator lamp is on,marking bias distortion is indicated. If the space indi-cator lamp is on, spacing bias distortion is indicated.Record the results.

(d) Turn power off at both stations.(4) Performance Standards. The maximum total

peak telegraph distortion permissable is 20%. Themaximum mark or space bias distortion permissable is12%.

Figure 6-19. Station to station total peak and average bias telegraph teat.

6 - 2 3

TM 11-5895-1012-10

Figure 6-20. In-Station total peak and average bias telegraph test.

6 - 2 4

TM 11-5895-1012-10

A P P E N D I X A

REFERENCES

The following publications are available to personnel assigned to the Technical Control Facility:A Pam 310-4 Index of Technical Manuals, Technical Bulletins, Supply Manuals, (Types 7, 8, and 9), Sup-

ply Bulletins, and Lubrication Orders.A Pam 310-7 US Army Equipment Index of Modification Work Orders.CAC 310-70-1 Volume I, DCS Technical Control Policy and Facilities; Volume II, DCS Technical Control

Procedures; Volume IV, DCS Technical Control Glossary.ECEO H500-12-64 DCS Technical Control Engineering Criteria.IL-STD-188-310 Subsystems Design and Engineering Standards for Technical Control Facilities.B 38-100 Reservation, Packaging, Packing, and Marking Materials, Supplies and Equipment Used

by the Army.B 43-0118 Field Instructions for Painting and Preserving Electronics Command Equipment Includ-

ing Camouflage Pattern Painting of Electrical Equipment Shelters.M 38-750 The Army Maintenance Management Systems (TAMMS).

A - 1

TM 11-5895-1012-10

A P P E N D I X B

A B B R E V I A T I O N S

B - 1

TM 11-5895-1012-10

B-2

TM 11-5895-1012

INDEX

AbbreviationsAdministrative storage

Circuit performanceExcessive signal levels

Quality control

Leased circuitsManagement

TestsTrend analysis

Circuit reroutingCatastrophic failure procedures

(Quality and maintenance)

Phase jitterUsing oscilloscopeUsing phase jitter meter

Signaling testIn-stationStation-to-station

Single tone interferenceTelegraph bias distortionTerminal impedance

Receive circuittransmit circuit

Test conditions

DestructionDistribution frames

EIR reportingExamples of operating TCF's

Berlin

Pentagon

Pirmasens

Fault isolationCircuit outagesCircuit status

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Improper terminations. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Performance monitoring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Government-owned circuits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Schedules . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Emergency procedures. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Normal procedures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Circuit test procedures

Audio frequency. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Composite signal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Envelope delay distortion. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Frequency response . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Harmonic distortion. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Idle channel noise. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Impulse noise . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Longitudinal balance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Net loss variation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Paragraph Page1-7. , 1-11-4. , 1-1

4-52.4-53.4-46.4-50.

4-47.4-48.4-54.4-49.4-55.4-51.

4-444-454-394-43

4-404-404-454-404-454-43

4-16. , 4-64-15. , 4-54-13. , 4-44-14. , 4-4

6-7. , 6-66-14. , 6-156-6. , 6-36-5. , 6-2

6-13. , 6-146-4. , 6-2

6-10. , 6-86-8. , 6-6

6-19. , 6-20

6-15. , 6-156-16. , 6-17

6-18. , 6-206-17. , 6-186-9. , 6-86-20. , 6-23

6-12. , 6-126-11. , 6-126-3. , 6-2

1-5. , 1-12-22. , 2-27

1-6. , 1-1

3-4. , 3-43-6.3-7. , 3-6

3-15. , 3-123-1. , 3-1

3-3.

4-23. , 4-124-37. , 4-30

Index 1

TM 11-5895-1012-10

Paragraph Page

Commercial outages. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Example procedures

Dc circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Voice channel ............. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Faults Baseband . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Dc . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Multichannel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Single VF channel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

G e n e r a l . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Procedures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Responsibilities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Restoration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . TCF functional areas . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Troubleshooting practices . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Voice frequency isolation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Forms and records . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Implementation of CSR's

ProceduresSample circuitTCF responsibilitiesTSO's

Index of publicationsInstalled facilities (See TCF facilities)

Maintenance tests(See circuit testing procedures)

New equipment acceptanceGeneralTCF responsibilitiesTest and acceptance

Operation practices and methodsOn-call circuitsOrderwires

DisciplineProcedureTypes

Service interruptionsCorrection of hazardous conditionsEmergencyScheduled . .

Station managementApproach. . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . .. . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . Facilities and usage . . . . . . . . . . . . . . . . . . . .

System management . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Technical controller duties . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . TELECON circuits . . . . . . . . . . . . . . . . . .

PatchingDc facilities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Precautions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Purpose . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Reporting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . VF facilities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Performance standardsConduct of tests . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Digital distortion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Recording test results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Technical schedules . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Test descriptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Test reporting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Power facilities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

4-34.

4-36.4-35.

4-32.4-33.4-31.4-30.

4-22.4-28.4-25.4-38.4-26.4-27.4-29.1-3.

4-20

4-274-20

4-184-194-184-174-124-124-154-304-164-164-171-1

4-474-474-464-461-1

4-58.4-59.4-57.4-56.1-2.

4-60. , 4-494-61. , 4-494-62. , 4-49

4-9. , 4-3

4-7. , 4-34-6. , 4-24-5. , 4-2

4-12. , 4-44-11. , 4-44-10. , 4-3

4-2. , 4-14-3. , 4-14-1. , 4-14-4. , 4-24-8. , 4-3

4-21. , 4-74-18. , 4-64-17. , 4-54-19. , 4-64-20. , 4-6

4-43. , 4-394-42. , 4-374-39. , 4-314-45. , 4-394-40. 4-314-41. , 4-374-44. , 4-39

2-23.2-29. , 2-33

Index 2

TM 11-5895-1012-10

Paragraph Page

QC test (see Circuit testing procedures)Quality control testing

(See circuit performance)

Representative TCF equipmentCircuit conditioning . . . . . .. . . . . .. . . . . .. . . . . .. . . . . .. . . . . . . . . . . . . . . . . .DLIU . . . . . . . . . . . . . . . . . . . . . . . .General . . . . . . . . . . . . . . . . . . . . . . . .Other conditioning equipment. . . . . . . . . . . . . . . . . . . . . . . .. . . . . .Patch panels

Dc . . . . . . . . . . . . . . . . . . . . . . . . . . . . .M i s c e l l a n e o u s . . . . . . . . . . . . . . . . . . . . . . . .VF and E&M . . . . . .. . . . . .. . . . . . . . . . . . . . . . . . . . . . . .

Signaling . . . . . . . . . . . . . . . . . . . . . . . . Test equipment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Rerouting (See circuit rerouting)

Scope . . . . . . . . . . . . . . . . . . . . . . . . Signal facilities. . . . . . . . . . . . . . . . . . . . . . . .

.Station cabling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Station maintenance

Checks and servicesDaily . . . . . . . . . . . . . . . . . . . . . . . .

Periods . . . . . . . . . . . . . . . . . . . . . . . . QuarterlyWeekly

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Cleaning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Prevention maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

System service interfacesAUTODIN . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . AUTOVON . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Common user network . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Communications facilities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Relay centers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Transmission media . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

TCF function . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . TCF interfaces

Ac power . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Classes of power. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Digital data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Distribution frames . . . . . . . . . . . . . . . . . . . . . . . . Generating equipment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . .

Internal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Miscellaneous . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Power. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Power distribution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Stating cabling. . . . . . . . . . . . . . . . . . . . . . . . . . . . Uninterruptible power supply (UPS) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Voice frequency . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Wideband . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

TCF purpose . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . TCF responsibilities. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

TCF signals. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Technical control facilityFunction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Purpose . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

2-31. , 2-362-39. , 2-542-30. , 2-342-33. , 2-37

2-36. , 2-382-37. , 2-452-35. , 2-332-34. , 2-372-33. , 2-50

1-1. , 1-12-17. , 2-152-18. , 2-242-19. , 2-242-20. , 2-262-21. , 2-27

6-3. , 5-15-2. , 5-15-5. , 5-25-4. , 5-15-6. , 5-25-1. , 5-1

2-13. , 2-92-12. , 2-82-8. , 2-4

2-10. , 2-62-7. , 2-4

2-11. , 2-82-9. , 2-4

2-2. , 2-1

2-25. , 2-282-24. , 2-232-16. , 2-122-18. , 2-242-22. , 2-272-26. , 2-282-20. , 2-262-29. , 2-332-23. , 2-272-27. , 2-292-21. , 2-272-28. , 2-302-17. , 2-152-19. , 2-242-1. , 2-1

2-3.2-6. , 2-3

2-14. , 2-11

2-2. , 2-12-15. , 2-112-1. , 2-1

ResponsibilitiesAdditional . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-5. 2-2General 2-3. , 2-1

Index 3

TM 11-5895-1012-10

Paragraph Page

To subscribers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Special assignments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Technical controllers duties. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Test equipment description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Test procedure introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Test procedures (see circuit testing

procedures)

2-4. 2-2

2-6. 2-34-4. , 4-26-2. , 6-16-1. , 6-1

*US GOVERNMENT PRINTING OFFICER 1978-703-128558

I n d e x 4

TM 11-5895-1012-10

Official:J.C. PENNINGTON

B r General, United States ArmyThe Adjutant General

(1)USACC (1)Armies (1)HISA (Ft Monmouth) (33)Ft Huachuca (2)Ft Richardson (ECOM Ofc) (1)

*Ft Carson (2)Ft Gillem (2)USASIGS (10)Svc Colleges (l)USAERDAA (1)USAERDAW (1)Sig FLDMS (1)

ARNG & USAR: None.For explanation of abbreviations used, see AR310-50.

BERNARD W. ROGERSGeneral, United States Army

Chief of Stuff

Figure FO-1. Simplified power distribution diagram.

Figure FO-2. Vf primary or equal level patch panel, interconnection diagram

Figure FO 2 Vf primary or equal level patch panel, interconnection diagram

TM 11-5895-1012-10

Figure FO-3. Primary dc patch panel, interconnection diagram.

TM 11-5895-1012-10

Figure FO-4. Dc patch panel (receive) with cut keys and lamps, interconnection diagram

TM 11-5895-1012-10

Figure FO-5. Dc patch panel (transmit) with cut keys and lamps, interconnection diagram

TM 11-5895-1012-10

Figure FO-6. TCF, Pirmasens, signal diagram

TM 11-5895-1012-10

Figure FO-7. TCF, Pirmasens, floor plan.

TM 11-5895-1012-10

Figure FO-8. TCF, Berlin, signal diagram.

TM 11-5895-1012-10

Figure FO-9. TCF, Berlin, floor plan

TM 11-5895-1012-10

Figure FO-10. TCF, Pentagon, signal diagram.

Figure FO-11. TCF, Pentagon, floor plan.

TM 11-5895-1012-10

Figure FO-12. TCF, Pentagon, floor plan.

Figure FO-13. Typical black digital circuit IDF connection diagram

TM 11-5895-1012-10

Figure FO 13. Typical black digital circuit IDF connection diagram

TM 11-5895-1012-10

Figure FO-14. Universal digital patch panel, interconnection diagram.

TM 11-5895-1012-10

Figure FO-15. Universal digital patch panel black send circuit strapping diagram

TM 11-5895-1012-10

Figure FO-16. Universal digital patch panel black receive circuit strapping diagram

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