network time server irig nts-100 600-201 · nts-201.man iii rev. a section vii 6-1 simple network...

Network Time ServerIRIG NTS-100

600-201

SERIAL NUMBER_______________Revision A

January 20, 1997

NTS-100 Network Settings

Record NTS-100 network settings below for quick reference.NTS-100 network setup instructions are detailed in Section 3.

Ethernet Address: ____________________________________

IP Address: ____________________________________

Subnet Mask: ____________________________________

Default Gateway: ____________________________________

Network Type: ____________________________________

Clock Type: ____________________________________

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SECTION I 1-1GENERAL INFORMATION 1-1

1.1 INTRODUCTION 1-11.2 LIMITED WARRANTY 1-11.3 LIMITATION OF LIABILITY 1-21.4 PROPRIETARY NOTICE 1-21.5 PHYSICAL SPECIFICATIONS 1-21.6 ENVIRONMENTAL SPECIFICATIONS 1-21.7 POWER INPUT SPECIFICATIONS 1-21.8 NTS-100 SYNCHRONIZATION OPTIONS 1-31.9 INTERNAL TIMING PERFORMANCE SPECIFICATIONS 1-31.10 NETWORK TIME PROTOCOLS 1-31.11 NETWORK TIME PROTOCOL SYNCHRONIZATION SPECIFICATIONS 1-41.12 INTERFACE SPECIFICATIONS 1-5

Ethernet Interface 1-5User RS-232 Serial I/O Interface 1-5LED Status Indicator 1-6Optional Time/Frequency Output Signals 1-6

IRIG B Time Code 1-61 PPS 1-610 MHz 1-6Alarm Output 1-7

SECTION II 2-7INSTALLATION 2-7

2.1 OVERVIEW 2-72.2 PROCEDURE 2-72.3 BASIC QUICK START INSTRUCTIONS 2-7

SECTION III 3-1OPERATION 3-1

3.1 INTRODUCTION 3-13.2 BASIC OPERATION 3-13.3 NETWORK INTERFACE 3-13.4 START-UP 3-13.5 GENERAL OPERATION 3-23.6 NTS-100 START-UP 3-23.7 FRONT PANEL INTERFACE 3-33.8 ALPHANUMERIC DISPLAY 3-33.9 TIME PUSH-BUTTON 3-33.10 STATUS PUSH-BUTTON 3-33.11 POSITION PUSH-BUTTON 3-33.12 KEYPAD OPERATION 3-33.13 SELECTING FUNCTIONS AND ENTERING DATA 3-43.14 KEYPAD FUNCTIONS 3-43.15 FUNCTION 00 - KEYPAD HELP FUNCTION 3-4

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3.16 FUNCTION 01 - TIME ZONE SELECT 3-53.17 FUNCTION 02 - 12/24 HOUR FORMAT SELECT 3-63.18 FUNCTION 03 - DATE AND TIME ENTRY 3-63.19 FUNCTION 04 - SERIAL I/O SETUP 3-73.20 FUNCTION 05 - TIME QUALITY ENABLE/SETUP 3-83.21 FUNCTION 06 - KEYPAD LOCK ENABLE 3-93.22 FUNCTION 13 - WORST-CASE TIME ERROR REQUEST 3-93.23 FUNCTION 18 - SOFTWARE VERSION REQUEST 3-103.24 FUNCTION 36 - NTS-100 CONFIGURATION ENTRY/REQUEST 3-103.25 FUNCTION 66 - DAYLIGHT SAVINGS ENABLE 3-123.26 FUNCTION 67 - LEAP SECOND INFORMATION 3-133.27 SERIAL I/O INTERFACE 3-143.28 SERIAL I/O FUNCTION LIST 3-143.29 FUNCTION 01 - TIME ZONE ENTRY/REQUEST 3-143.30 FUNCTION 02 - 12/24 HOUR FORMAT ENTRY/REQUEST 3-153.31 FUNCTION 03 - TIME/DATE ENTRY/REQUEST 3-163.32 FUNCTION 05 - TIME QUALITY ENABLE/SETUP 3-173.33 FUNCTION 08 - CONTINUOUS TIME ONCE PER SECOND ENABLE 3-173.34 FUNCTION 09 - TIME ON REQUEST ENABLE 3-183.35 FUNCTION 11 - TIME OUTPUT FORMAT ENTRY/REQUEST 3-193.36 FUNCTION 13 - WORST-CASE TIME ERROR REQUEST 3-213.37 FUNCTION 18 - SOFTWARE VERSION REQUEST 3-223.38 FUNCTION 36 - NTS-100 CONFIGURATION ENTRY/REQUEST 3-22

Ethernet Address 3-22IP Address 3-22Subnet Mask 3-23Default Gateway 3-23Network Packet Type 3-23Complete NTS-100 Network Configuration 3-24Clock Type 3-24Clock Accuracy 3-24

3.39 FUNCTION 66 - DAYLIGHT SAVINGS ENABLE 3-253.40 FUNCTION 67 - LEAP SECOND INFORMATION 3-27

SECTION IV 4-1NOT USED 4-1

SECTION V 5-1IRIG B SYNCHRONIZATION OPTION 5-1

5.1 IRIG B SETUP AND OPERATION 5-1

SECTION VI 5-1MD5 AUTHENTICATION PROTOCOL 6-1

6.1 MD5 INTRODUCTION 6-16.2 TRUETIME NTP MD5 OPERATION 6-16.3 KEYPAD MD5 CONFIGURATION 6-26.4 SERIAL MD5 KEY CONFIGURATION 6-3

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SECTION VII 6-1SIMPLE NETWORK MANAGEMENT PROTOCOL 7-1

7.1 SNMP INTRODUCTION 7-17.2 SNMP CONFIGURATION 7-17.3 NTP PARAMETERS 7-47.4 SNMP TRUETIME ENTERPRISE MIB VARIABLE DEFINITIONS 7-4

The Enterprise 7-4TrueTime's Enterprise MIB 7-4Groups in TrueTime Enterprise MIB: 7-4Display Strings 7-5

7.5 THE TRAPMSG GROUP 7-5trapMsgNtpAlarm OBJECT-TYPE 7-5trapMsgSnmpAuthFail OBJECT-TYPE 7-5

7.6 THE NTP GROUP 7-6ntpInPkts OBJECT-TYPE 7-6ntpOutPkts OBJECT-TYPE 7-6ntpInErrors OBJECT-TYPE 7-6ntpAuthFail OBJECT-TYPE 7-6ntpDesiredAcc OBJECT-TYPE 7-6ntpEstErr OBJECT-TYPE 7-7ntpSysLeap OBJECT-TYPE 7-7ntpSysHostMode 7-8ntpSysStratum OBJECT-TYPE 7-8ntpSysPoll OBJECT-TYPE 7-8ntpSysPrecision OBJECT-TYPE 7-9ntpSysRootDelay OBJECT-TYPE 7-9ntpSysRootDisp OBJECT-TYPE 7-9ntpSysRefClockIdent OBJECT-TYPE 7-9

7.7 THE NTSCONTROL GROUP (PRELIMINARY) 7-10ntpControlInput OBJECT-TYPE 7-11ntpControlOutput OBJECT-TYPE 7-11

7.8 GPS GROUP VARIABLES 7-11gpsGroupValid OBJECT-TYPE 7-12gpsNumTrackSats OBJECT-TYPE 7-12gpsNumCurrentSats OBJECT-TYPE 7-12gpsSatTrackMode OBJECT-TYPE 7-12gpsSatMaxSigStrength OBJECT-TYPE 7-13gpsAltitude 7-13gpsLongitude 7-13gpsLatitude 7-13

7.9 ACTS GROUP VARIABLES 7-14actsGroupValid OBJECT-TYPE 7-15actsBaudRate OBJECT-TYPE 7-15actsFailRedial OBJECT-TYPE 7-15actsMaxCallPeriod OBJECT-TYPE 7-15actsPhoneNum OBJECT-TYPE 7-15actsNumberOfCalls OBJECT-TYPE 7-16actsGoodCalls OBJECT-TYPE 7-16actsBadCalls OBJECT-TYPE 7-16

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actsFailedInit OBJECT-TYPE 7-16actsNoDialTone OBJECT-TYPE 7-16actsNoCarrier OBJECT-TYPE 7-17actsBusyLine OBJECT-TYPE 7-17actsNoAnswer OBJECT-TYPE 7-17actsBadReply OBJECT-TYPE 7-17actsNoOnTimeMark OBJECT-TYPE 7-17

APPENDIX ANTP v 3.0 DATA FORMAT per RFC1305

A-1 NTP DATA PACKETA-2 SNTP V 3.0 DATA FORMAT PER RFC1361

APPENDIX BTIME PROTOCOL per RFC868

B-1 INTRODUCTIONB-2 THE TIME FORMAT

APPENDIX CIRIG B TIME CODE

C-1 INTRODUCTIONC-2 IRIG B CODE FORMATC-3 EMBEDDED WORST-CASE TIME ERROR FLAGS

APPENDIX DDETAILED DRAWINGS / BILL OF MATERIALS

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1.

SECTION IGENERAL INFORMATION

1.1 INTRODUCTION1.1.1 This manual provides the user of the NTS-100 Network Time Server all of the

information necessary to properly install, operate and utilize its features.1.1.2 The information in this manual includes any normal maintenance and adjustment data

that may be required to facilitate field repairs.1.1.3 The purpose of the Model NTS-100 is to provide Internet Protocol (IP) network time

synchronization, over Ethernet connected networks, via the Network Time Protocol(NTP) developed by Dr. David Mills at the University of Delaware. In providing thissynchronization, the NTS-100 operates as a “server”. The NTS-100 currently supportsversions 2.0, RFC 1119 and 3.0, RFC 1305 of the NTP, as well as the Simple NetworkTime Protocol (SNTP), RFC1361. In addition, the NTS-100 will respond to TIMEprotocol requests, RFC868. Refer to Appendices A and B of this manual for detailsregarding these protocols.

1.1.4 The NTS-100 obtains its timing information from one of four synchronization sourceoptions: User 1PPS, User IRIG-B, Internal GPS, or the Automated Computer TimeService (ACTS).

1.1.5 In addition to performing the functions of an NTP Server, the NTS-100 provides optionaltiming and frequency outputs whose accuracy’s are commensurate with thesynchronization source being input to the NTS-100. These optional outputs include1PPS, IRIG-B and 10MPPS.

1.2 LIMITED WARRANTY1.2.1 Each new product manufactured by TrueTime is warranted for defects in material or

workmanship for a period of one year from date of shipment ("Limited Warranty"). Defects in material or workmanship found within that period will be replaced or repaired,at TrueTime's option, without charge for material or labor, provided the customer returnsthe equipment, freight prepaid, to the TrueTime factory under this limited warranty.TrueTime will return the repaired equipment, freight prepaid, to the customer's facility. This one year Limited Warranty does not apply to any software or to any product notmanufactured by TrueTime.

1.2.2 If on-site warranty repair or replacement is required, the customer will be charged thethen current field service rate for portal-to-portal travel time plus actual portal-to-portaltravel charges. There is no charge for on-site warranty repair labor.

1.2.3 Products not manufactured by TrueTime but included as integral part of a system (e.g.peripherals, options) are warranted for 90 days, or longer as provided by the originalequipment manufacturer, from date of shipment.

1.2.4 Aside from the Limited Warranty set forth above, TrueTime makes no other warranties,express or implied, of merchantability, fitness for purpose or of any other kind ordescription whatsoever.


1.2.5 By purchasing any product manufactured by TrueTime, the buyer consents to andagrees with TrueTime that as a result of the exclusion of all warranties, expressed orimplied, of merchantability, fitness for purpose, or otherwise, except for the limitedone-year warranty for defects in material and workmanship for products manufactured byTrueTime, that the Buyer has the sole responsibility to assess and bear all lossesrelating to (1) the ability of the product or products purchased to pass without objectionunder the contract description among merchants and buyers in the trade; (2) theconformity of the product or products to fair average quality within its contractdescription; (3) the fitness of the product for the ordinary purposes for which suchproduct is used; (4) the consistency of quality and quantity within each unit of product orproducts and among all units involved; (5) the adequacy of containers, packaging andlabeling of the product or products; (6) the conformity of the product, promises oraffirmations of fact (if any) made on its label or container; and (7) the conformity of theproduct to standards of quality observed by other merchants in the trade with respect toproducts of similar description.

1.3 LIMITATION OF LIABILITY1.3.1 By purchasing any product from TrueTime the Buyer consents to and agrees that the

Buyer's sole and exclusive remedy for any damages or losses incurred by the Buyer as aresult of TrueTime's breach of its one-year Limited Warranty for defects in materials andworkmanship or otherwise in connection with any claim respecting the product shall belimited to the repair or replacement of the product or a refund of the sales price of theproduct.

1.3.2 In no event shall the Buyer be entitled to recover consequential damages or any otherdamages of any kind or description whatsoever.

1.4 PROPRIETARY NOTICE1.4.1 THIS DOCUMENT, WHETHER PATENTABLE OR NON-PATENTABLE SUBJECT

MATTER, EMBODIES PROPRIETARY AND CONFIDENTIAL INFORMATION AND ISTHE EXCLUSIVE PROPERTY OF TRUETIME, INC. IT MAY NOT BE REPRODUCED,USED OR DISCLOSED TO OTHERS FOR ANY PURPOSE EXCEPT THAT FORWHICH IT IS LOANED, AND IT SHALL BE RETURNED UPON DEMAND.

1.5 PHYSICAL SPECIFICATIONS1.5.1 The NTS-100 is a 19” rack mounted product with the following physical specifications:

NTS-100 Chassis Size: 1.75 in x 17.00 in x 9.70 in(4.45 cm x 43.18 cm x 24.64 cm)

NTS-100 Chassis Weight: 4.1 lb max. (3.175 Kg)

1.6 ENVIRONMENTAL SPECIFICATIONSOperating Temperature: +32° to +140°F (0° to +60°C)Storage Temperature: -40° to +185°F (-40° to +85°C)Humidity: 95%, non-condensing

1.7 POWER INPUT SPECIFICATIONSVoltage: 95-260 Vac


Frequency: 47-440 HzPower Consumption: <15W

1.8 NTS-100 SYNCHRONIZATION OPTIONS1.8.1 The NTS-100 can be factory configured to synchronize to four different types of input

signals:

• User supplied, on-time 1PPS with operator input of date and time at the next secondand any leap second information

• User supplied IRIG-B, AM or TTL, with operator input of date and leap secondinformation

• Automated Computer Time Service (ACTS) of the National Institute of Standards andTechnology (NIST) via dial-up modem, which requires no operator input of any timeinformation

• Internal NAVSTAR GPS core module, which requires no operator input of any timeinformation

See Manual Section 5 for details of the synchronization source option configured for yourunit.

1.9 INTERNAL TIMING PERFORMANCE SPECIFICATIONS1.9.1 The absolute time and frequency characteristics of the NTS-100 are essentially those of

the input synchronization source. The relative synchronization characteristics given herereflect the capabilities of the NTS-100 to preserve the time and frequency characteristicsof the synchronization source being provided to the NTS-100. Refer to Manual Section 5for details concerning the time and frequency characteristics of the synchronizationsource option of interest.

1.9.2 The NTS-100 output signal timing and frequency specifications relative to the inputsynchronization source are:

1PPS Output (Option)Accuracy: ±1 µs

Amplitude Modulated IRIG B Output (Option)Accuracy: ±10 µs

10 MHz Output (Option)Accuracy: ±1 in 10-11 @ tau = 1 day

1.9.3 During a synchronization input outage, following initial synchronization of the NTS-100 tothe input synchronization source, the timing and frequency outputs from the NTS-100 willdiverge from the input at the rate of approximately 2 parts in 106 , if the ambienttemperature is maintained within ±3°C.

1.10 NETWORK TIME PROTOCOLS1.10.1 The NTS-100 will respond to time synchronization requests from hosts using these User

Datagram Protocol/Internet Protocols (UDP/IP):NTP ver. 2.0 UDP Port 123 RFC1119


NTP ver. 3.0 UDP Port 123 RFC1305**SNTP UDP Port 123 RFC1361TIME UDP Port 37 RFC868

1.10.2 Refer to Appendices A and B of this manual for detailed information regarding theseprotocols as implemented by the NTS-100.** The NTS-100 does not implement the “authenticator field” of the NTP packet asdescribed in Appendix C of RFC1305.

1.11 NETWORK TIME PROTOCOL SYNCHRONIZATION SPECIFICATIONS1.11.1 The NTS-100 hardware is designed specifically to implement the NTP server function.

As such it was carefully designed to operate with the TrueTime Mark III real timeoperating system to minimize the unknown latencies in timestamping the received andtransmitted NTP packets. The NTP packet timestamp accuracy specifications are:

Received Timestamp ±10 µs, relative to synchronization sourceTransmitted Timestamp ±10 µs, relative to synchronization source

1.11.2 At these levels of accuracy, the realizable NTP synchronization accuracy of any clienthost is determined by the quality of the synchronization source and the repeatability ofthe network and client delays, not by the NTS-100 timestamp uncertainty.


1.12 INTERFACE SPECIFICATIONS

Ethernet InterfaceFrame Format: DIX Ethernet (Ethernet II) or IEEE 802.3 with 802.2

headersConnector: AUI, female 15-pin D subminiature

Pin Assignment

Pin Assignment1 GND2 CI+3 DO+4 GND5 DI+6 GND7 NC8 GND9 CI-

10 DO-11 GND12 DI-13 +12V14 GND15 NC

User RS-232 Serial I/O InterfaceData: Time, day of year through milliseconds, in ASCII

characters, output once per second or on request. Also special functions as listed in Section III.

Data Rates: User selectable, 300, 600, 1200, 2400, 4800, and 9600bps, 19200

Data Bits: User selectable, 7 or 8Parity: User selectable, even, odd or noneStop Bits: User selectable, 1or 2Connector: Male 9-pin D subminiature, wired as DTE


Pin Assignment

Pin Assignment1 NC2 RXUSER3 TXUSER4 NC5 GND6 NC7 NC8 NC9 NC

LED Status Indicator1.12.1 A front panel mounted, bi-color LED which reflects the status of the NTS-100:

Solid Red: Alarm State, no synchronizationSolid Orange: Alarm State, synchronization present, not fully lockedBlinking Green: Fully Operational State

1.12.2 The Solid Red and Solid Orange conditions correspond with the Open Collector AlarmOutput high impedance, or Alarm state. The Blinking Green condition corresponds withthe Open Collector Alarm Output low impedance, or Normal state.

Optional Time/Frequency Output Signals1.12.3 A combination of up to two output signals are available from the NTS-100 via panel

mounted, female BNC connectors. The available output signals are:

IRIG B Time CodeFormat: IRIG B 122Carrier: 1 KHz.Amplitude: 5.0 Vp-p high, 1.5 Vp-p low, no loadOutput Z: 600 ohmsConnector: Female BNC

1 PPSAmplitude: ACMOS levelsOutput Z: 22 ΩConnector: Female BNC

10 MHzAmplitude: ACMOS LevelsOutput Z: 22 ΩConnector: Female BNC


Alarm Output1.12.4 The purpose of the alarm output is to provide an indication of an out of service condition

caused by initial power up, extended period without synchronization input, or hardwarefailure. This output is asserted whenever the Leap Indicator bits of the NTP packet sentby the NTS-100 are set to 3, the alarm condition.

Open Collector: Alarm Status is high impedance stateConnector: Female BNC

2.

SECTION IIINSTALLATION

2.1 OVERVIEW2.1.1 The user must provide the NTS-100 with a source of power and synchronization, an

Ethernet network connection, and set-up parameters. The NTS-100 Network TimeServer is capable of basic operation without any RS-232 connection once the essentialnetwork and operating parameters have been entered. The NTS-100 retains allconfiguration data in Electrically Erasable/Programmable Read Only Memory(EEPROM).

2.2 PROCEDURE2.2.1 The NTS-100 is designed to be mounted in a 19” rack enclosure. It is necessary only to

make the power, synchronization and network input connections (and any optional outputconnections) to the NTS-100. The synchronization input for the NTS-100 is described inmore detail in Section 5 of this manual. The network connection is made via the AUIconnector and any required Media Access Unit (MAU). Once these connections havebeen made, turn on the unit and follow the instructions below.

2.3 BASIC QUICK START INSTRUCTIONS2.3.1 Refer to the Synchronization Option described in Section 5 of this manual and make the

appropriate input connection. After powering up the module, use the front panel keypad,or connect a PC or other RS-232 terminal to the Serial I/O port Male DB9 connector toinput the required NTS-100 parameters. When using the Serial I/O port, a null modemadapter may be required.

2.3.2 Network configuration information must be sent to the NTS-100 using Keypad or SerialI/O Function 36. The IP address, subnet mask, default gateway, and network packettype must be entered in order to interface with a network. The clock accuracy shouldalso be entered for transmission in the appropriate fields of the NTP packet. See manualSection 3 for a detailed description of Keypad and Serial I/O Function 36 and Appendix Afor details of the NTP packet.

2.3.3 Refer to manual Section 5 for specific setup instructions which pertain to thesynchronization source option of this unit.

2.3.4 Verify that the NTS-100 is running by pressing the “TIME” push-button on the front panel.The days through seconds time being generated by the NTS-100 will be displayed on the

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front panel display. The LED status indicator will illuminate RED or ORANGE during thistime and the Open Collector Alarm Output will be in a high impedance state. It may takeseveral minutes for LOCK to occur, depending upon the synchronization input option. When the synchronization option is GPS, allow at least five minutes for the NTS-100 toacquire lock. Once locked, the ? character will change to a space character, the OpenCollector Alarm Output will transition to a low impedance state and the LED statusindicator will illuminate GREEN, blinking at a 1 Hz rate.

2.3.5 Once the NTS-100 is running properly, the unit should respond to PING, TIME and NTPpackets. If it does not, check the connection to the network and all Function 36 networkconfiguration parameters.

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3.

SECTION IIIOPERATION

3.1 INTRODUCTION3.1.1 The NTS-100 Module provides extremely accurate time over an Ethernet connection

when synchronized via one of four input options:3.1.2 The first option is a 1 Pulse Per Second input. In this configuration, the date and time of

day to the nearest second must be set via the RS232 interface. The time is thenincremented on each rising edge of the input 1PPS. The operator must also provideinformation about upcoming leap second events via the RS232 interface.

3.1.3 The second option is to synchronize the NTS-100 module to an IRIG B source. In thisconfiguration, the user must provide the correct date as well as information about comingleap second events via the RS232 interface.

3.1.4 The third option is to synchronize via an internal dial-up modem to the AutomatedComputer Time Service operated by the National Institute of Standards and Technology(NIST). Between calls to this time service, the NTS-100 will “flywheel” on its internaloscillator. The user may set the desired accuracy and the NTS-100 will set the intervalbetween calls required to maintain the desired accuracy. This option requires nooperator input to maintain accurate UTC time and automatically handles leap secondevents.

3.1.5 The final, and most accurate option is to synchronize the NTS-100 module to the USNOby use of the NAVSTAR Global Positioning System (GPS). This option requires nooperator input to maintain accurate UTC time and automatically handles leap secondevents.

3.2 BASIC OPERATION3.2.1 This Section provides a complete description of the basic operation of the NTS-100. The

Synchronization Option specific operation details are contained in Section 5.

3.3 NETWORK INTERFACE3.3.1 TrueTime’s NTS-100 module supports RFC-868, RFC-1119, RFC-1305 and RFC-1361.

An NTP or SNTP client daemon compatible with the user’s computer platform isrequired for accurate network synchronization. The daemon must be told the NTS-100IP address.

3.4 START-UP3.4.1 On power up, the NTS-100 module will check its EEPROM for valid configuration data. If

configuration data is valid and present, then the NTS-100 will attempt to synchronize itsinternal time to the synchronization source, if that source is IRIG-B, GPS or ACTS. If thesource is 1PPS, then the NTS-100 will wait for the operator to initiate the synchronizationprocedure.

3.4.2 Once the NTS-100 has synchronized itself to the source, then it will be ready to respondto any requests that it receives over the network from supported protocols. During

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interruptions of the synchronization input, the NTS-100 will estimate the quality of thetime it is able to provide to clients and update the fields of the NTP packet appropriately. In addition, the time quality character of the Serial I/O Function 08 string and the “worstcase time error” reported by Function 13 are also updated during such interruptions. TheNTS-100 will provide NTP server operation until the Function 13 “worst case time error”has exceeded the value of the Root Dispersion field set in the NTP packet. SeeAppendix A for details on this behavior.

3.5 GENERAL OPERATION3.5.1 The two most-used functions (TIME, and STATUS) have been assigned to front-panel

pushbuttons. The POSITION pushbutton has no function on the NTS-100-IRIG,NTS-100-ACTS or NTS-100-1PPS. All functions may be accessed via the front-panelkeypad and viewed on a front-panel alphanumeric display or accessed via the Serial I/Ointerface and viewed on a monitor.

3.6 NTS-100 START-UP3.6.1 At power up, the unit will present messages on the small front panel display to indicate

the version of software installed in the unit, and how to invoke the keypad help function. The first message is the version of the system software. For example:

TRUETIME NTSsys ver 014

3.6.2 After a few seconds, the display will show:Press func, 0, 0for help.

3.6.3 Then the display will show the version of the clock-specific software:NTS V1.003 (Example)182-7002v001

3.6.4 After a few seconds, the display will show the status display, which will remain until akeypad function is invoked, or the "TIME" button is pressed.

3.6.5 It should be noted that the text of the version messages and status display will vary frommodel to model and version to version.

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3.7 FRONT PANEL INTERFACE3.7.1 The NTS-100 front panel is the primary user interface. Input is via three front panel

push-buttons and a 16-key keypad. Output is via the two-line 32-character alphanumericLCD. The alphanumeric display shows status and various function displays.

3.8 ALPHANUMERIC DISPLAY3.8.1 The alphanumeric display is used both to display current clock status and as a means of

communicating information accessible through the NTS-100 list of keypad functions.3.8.2 When not being used for keypad function operation, the alphanumeric display can be set

to display (in real time) the current clock mode or current time with calendar day andyear.

3.9 TIME PUSH-BUTTON3.9.1 Pressing the TIME push-button places the equivalent time-of-year and the date on the

alphanumeric display. The format of the date is day-of-week, month, day-of-month, year.

3.10 STATUS PUSH-BUTTON3.10.1 The Status Pushbutton displays the status of the NTS-100. The display will indicate that

the unit is either locked or unlocked to its synchronization input source. See Section 5 ofthis manual for a detailed description of the status display for the synchronization inputoption in your unit.

3.10.2 Additionally, PRESSING THE STATUS BUTTON WILL ABORT ANY KEYPADFUNCTION CURRENTLY IN PROGRESS. If an incorrect function was entered, or if thealphanumeric display shows something unexpected, pressing the status pushbutton willabort the function with no action taken by the function.

3.11 POSITION PUSH-BUTTON3.11.1 Pressing the POSITION button will have no effect on the operation of an IRIG, ACTS, or

1PPS synchronized NTS-100.

3.12 KEYPAD OPERATION 3.12.1 The 16-key panel-mounted keypad consists of numeric keys "0" through "9", arrow keys

"up","down","right", and "left", a clear key "CLR" and the function/enter key"FUNC/ENTR". Refer to "SELECTING FUNCTIONS AND ENTERING DATA" in thissection before attempting function entries. The following rules are for keypad functionentry:

• STATUS, or TIME should be on the alphanumeric display before starting a function.If not, press the "STATUS" button.

• It takes several seconds for some functions to appear. If nothing happens afterseveral seconds, press "STATUS", then try again.

• When pressing keypad buttons, hold the button for 1/4 second to reduce contactbounce and insure the key is recognized. Short "pokes" may result in bad entries.

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• To enter a specific function, first press FUNC/ENTR then the function number. Besure to include the leading zeros for function numbers lower than ten. If the functionnumber is currently unassigned or not implemented the alphanumeric display willshow the "Function not implemented" message then revert to STATUS.

• When entries are complete and the display shows the desired data, press"FUNC/ENTR".

• The "CLR" key will clear data entered. Example: If you intended to enter an IPAddress of 255.255.255.240, but notice just prior to pressing the "FUNC/ENTR" thatyou inadvertently entered 255.255.255.255, press "CLR". The display will revert tothe previous value. Then re-enter 255.255.255.240 and press "FUNC/ENTR". Toverify your entry, press "FUNC/ENTR" and the appropriate function number and thedata will display. To leave this function unchanged simply press the "STATUS"button. Your entry will remain unchanged and the display will have reverted back to"STATUS".

• Use the left or right arrow keys to move the cursor beneath the character that youwish to edit. Use the up or down arrow keys to scroll through the possible choices forthat character.

3.13 SELECTING FUNCTIONS AND ENTERING DATA3.13.1 The various keypad functions are listed in the following KEYPAD FUNCTION LIST.

Some of these functions are optional and may not be included in your unit. If in doubt asto whether your unit includes a particular function, try it. The alphanumeric displayshows the message "Function not implemented" if the function is not in your firmware. NOTE: Most of the functions must be re-requested to obtain the most current value.

3.14 KEYPAD FUNCTIONSF00 Keypad Help FunctionF01 Time Zone Entry/RequestF02 12/24 Hour ModeF03 Time/Date Entry/RequestF05 Time Quality Enable/SetupF06 Keypad Lock EnableF13 Worst-case Time Error RequestF18 Software Version RequestF36 NTS-100 Configuration Entry/RequestF66 Daylight Savings EnableF67 Leap Second Information Entry/Request

3.15 FUNCTION 00 - KEYPAD HELP FUNCTION3.15.1 Use keypad function 00 to obtain a short description of all keypad functions available.3.15.2 Press "FUNC ENTR", then "0" "0". The display will show:

up, down keys to view list...

3.15.3 Press any key to see the next display:Func/enter key to call function

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3.15.4 Press any key to see the next display, the first entry in the keypad function descriptionlist:

F01: Sets timezone

3.15.5 Now, the list of available keypad functions can be viewed by pressing the up or downarrow keys. Each entry in the list gives the function number and a short description of thefunction's purpose. If the "FUNC/ENTR" is pressed, the function being displayed will beinvoked. When a function so invoked is finished, the display will revert to "status".

3.15.6 The help function can be exited without invoking a function by pressing the "TIME", or"STATUS" button.

3.16 FUNCTION 01 - TIME ZONE SELECT3.16.1 Use function 01 to enter your time-zone offset. The initial out-of-the-box default is

00:00 (UTC). The default upon subsequent power-ups will be the value used beforepower-down. The acceptable range of offsets are +12:00 to -12:00 hours.

3.16.2 Press "FUNC/ENTR", then "0" "1". The display will showTime zone hr:min±00:00

3.16.3 Press the right or left arrow keys to position the cursor beneath the character that youwish to change. Press the up or down arrow keys to scroll through the possible choices. Alternately, directly enter the numbers using the keypad. The cursor will advance to thenext digit automatically. When the display shows the desired time-zone offset press"FUNC/ENTR" to enter your choice.

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3.17 FUNCTION 02 - 12/24 HOUR FORMAT SELECT3.17.1 Use function 02 to select either the 12-hr or 24-hr time display format. Upon initial out-

of-the-box power-up the default is the 24-hr format. Upon subsequent power-ups thedefault will be whatever the format was before the previous power-down.

3.17.2 Press "FUNC/ENTR", then "0" "2". The display will show12/24 hr Format or 12/24 hr Format24 12

3.17.3 Press the up or down arrow keys to toggle between 24 and 12. When the display showsthe desired format, press "FUNC/ENTR" to enter your choice.

3.18 FUNCTION 03 - DATE AND TIME ENTRY3.18.1 Use function 03 to enter time and date. The initial out-of-the-box default is UTC date and

time. The time-of-year before power-down will be the default upon subsequent power-ups.

3.18.2 Press "FUNC/ENTR", then "0" "3". The display will show:Date-time or Date-timeUTC Local

3.18.3 Press the up or down arrow keys to toggle between "UTC" and "Local" depending onwhich you intend to enter. When the display shows your choice, press "FUNC/ENTR"again and the display will show:

Date-timeMM/DD/YY

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where MM is the month, DD is the day and YY is the year. Press the right or left arrowkeys to move the cursor beneath the digit that you wish to change. Press the up ordown arrow keys to scroll through the possible choices. Alternately, directly enter thenumbers using the keypad. The cursor will advance to the next digit automatically. NOTE: Although an illegal date entry will display, the entry will not be accepted.

3.18.4 Press "FUNC/ENTR" again and the display will showDate-timeHH:MM:SS

where HH is the hours, MM is the minutes and SS is the seconds.

3.18.5 Press the left or right arrow keys to position the cursor beneath the digit that you wish tochange. Press the up or down arrow keys to scroll through the possible choices. Alternately, directly enter the numbers using the keypad.

3.18.6 The cursor will advance to the next digit automatically. Press "FUNC/ENTR" to enter thedata. Only valid dates may be entered.

3.19 FUNCTION 04 - SERIAL I/O SETUP3.19.1 Use function 04 to configure the Serial I/O port. The initial out-of-the-box default values

are:Baud Rate: 9600Data Bits: 7Parity: EvenStop bits: 1

3.19.2 The default values on subsequent power-ups will be those in use prior to the previouspower-down.

3.19.3 Press "FUNC/ENTR, then "0" "4". The display will showSer port setupBaud rate 9600

3.19.4 Press the up or down arrow keys to scroll through the possible baud rate choices. Whenthe display shows the desired baud rate, press "FUNC/ENTR" again and the display willshow:

Ser port setupData bits 7

3.19.5 Press the up or down arrow keys to toggle between 7 and 8 data bits choices. When thedisplay shows the desired choice, press "FUNC/ENTR" again and the display will show:

Ser port setupParity even

3.19.6 Press the up or down arrow keys to toggle between even or odd parity. When thedisplay shows the desired parity press "FUNC/ENTR". The display will show:

Ser port setupStop bits 1

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3.19.7 Press the up or down arrow keys to toggle between 1 and 2 stop bits. When the displayshows the desired choice, press "FUNC/ENTR" to enter all the serial port data.

3.20 FUNCTION 05 - TIME QUALITY ENABLE/SETUP3.20.1 Both the front-panel numeric display and the Serial I/O time output string indicate time

quality. Refer to Serial I/O FUNCTION FO8 - CONTINUOUS TIME ONCE PERSECOND for a description of the time quality indication in the Serial I/O time outputstring. As shipped the time quality indication is enabled and the thresholds are:

First threshold 10µsSecond threshold 100 µsThird threshold 1000 µsFourth threshold 10000 µs

3.20.2 Use Function 05 to enable or disable the time quality indication or set the worst-case-error thresholds. Press "FUNC/ENTR", then "0" "5". The display will show:

Time quality or Time qualityon off

3.20.3 Press the up or down arrow keys to toggle between "on" and "off". When the displayshows the desired state, press "FUNC/ENTR". The display will show:

First tq flag:00000010000ns

3.20.4 or the current value. Press the right or left arrow keys to position the cursor beneath thedigit that you wish to change. Press the up or down arrow keys to scroll through thepossible digit choices. Alternately, directly enter the numbers using the key pad. Thecursor will advance to the next digit automatically. When the display shows the valuethat you desire for the first time quality threshold, press "FUNC/ENTR". The display willshow:

Second tq flag:00000100000ns

or the current value. Press the right or left arrow keys to position the cursor beneath thedigit that you wish to change. Press the up or down arrow keys to scroll through thepossible digit choices. Alternately, directly enter the numbers using the key pad. Thecursor will advance to the next digit automatically. When the display shows the value thatyou desire for the second time quality threshold, press "FUNC/ENTR". The display willshow:

Third tq flag:00001000000ns

or the current value. Press the right or left arrow keys to position the cursor beneath thedigit that you wish to change. Press the up or down arrow keys to scroll through thepossible digit choices. Alternately, directly enter the numbers using the key pad. Thecursor will advance to the next digit automatically. When the display shows the value thatyour desire for the third time quality threshold, press "FUNC/ENTR". The display will show:

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Fourth tq flag:00010000000ns

or the current value. Press the right or left arrow keys to position the cursor beneath thedigit that you wish to change. Press the up or down arrow keys to scroll through thepossible digit choices. Alternately, directly enter the numbers using the key pad. Thecursor will advance to the next digit automatically. When the display shows the value thatyou desire for the fourth time quality threshold, press "FUNC/ENTR" to enter all of the data.The acceptable threshold values are 40000000000 ns to 00000000010 ns.

3.21 FUNCTION 06 - KEYPAD LOCK ENABLE3.21.1 Use function 06 to enable or disable the keypad. The keypad lock function, when

enabled, prevents unauthorized or accidental entries on the keypad. The initial out-of-the-box default is "off". The default upon subsequent power-ups will be the same as itwas on the previous power-down.

3.21.2 Press "FUNC/ENTR" then "0" "6". The display will showKeypad Lock or Keypad Lockon off

3.21.3 Press up or down arrow keys to toggle between "on" and "off". When the display showsthe desired choice, press "FUNC/ENTR". After the keypad lock is enabled, any attemptto enter a function on the keypad (except keypad function 06) will result in the message"Keypad locked" or "Function not implemented".

3.22 FUNCTION 13 - WORST-CASE TIME ERROR REQUEST3.22.1 Use function 13 to display the worst-case time error due to oscillator drift during periods

when synchronization input is not present.3.22.2 Press "FUNC/ENTR", then "1" "3". The display will show:

Time errorOver range

if the unit has not yet acquired valid time or:

Time error ±00.000010000

if the unit has acquired valid time. If the NTS-100 acquired valid time but subsequentlylost lock to the signals, then the time displayed and output will begin to drift. This drift isdependent on the stability of the internal oscillator, and the accuracy to which it had beenset on frequency prior to the outage. The processor calculates and displays in secondsthe worst-case time based on the stability of the oscillator in use.

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3.23 FUNCTION 18 - SOFTWARE VERSION REQUEST3.23.1 Use keypad function 18 to obtain information about the current version of the software

installed in the unit.3.23.2 Press "FUNC/ENTR", then "1" "8". The display will show, for example:

TRUETIME NTS-100sys ver 002

3.23.3 Press any of the arrow keys, to change the display to the clock-specific version. Forexample:

NTS v1.003182-6007v001

3.23.4 Repeated presses of arrow keys will switch back and forth between the two displays.3.23.5 The two examples shown indicate that the system software is version 14, and the clock-

specific software is version 1.011, PART NO. 182-6007v001.3.23.6 To return to the status display, press the "FUNC/ENTR", or "STATUS" button.

3.24 FUNCTION 36 - NTS-100 CONFIGURATION ENTRY/REQUEST3.24.1 Use function 36 to set the network parameters of the NTS-100 unit.3.24.2 Press “FUNC/ENTR”, then “3” ”6”. The display will show:

Display EthernetAddress

3.24.3 Use the up and down keys to scroll among the major selections for function 36: DisplayEthernet Address, Clock Type, Display/Setup Clock Accuracy, Display/Setup NetworkType, Display/Setup Default Gateway, Display/Setup Subnet Mask, Display/Setup IPAddress, and Display/Setup IRIG Lock Quality. Pressing "FUNC/ENTR" while thedesired action is displayed allows the user to view and/or modify the NTS-100parameters. At any time a major selection is displayed, the Up and Down arrow keyscan be used to move to another major selection. This eliminates the need to view eachof the function 36 parameters if it is only desired to change one parameter.

3.24.4 Pressing "FUNC/ENTR" on “Display Ethernet Address” displays the Ethernet Address ofthe unit as shown here:

Company:00-A0-69 (Fixed)Unit:00-02-4F (Example)

3.24.5 Press "FUNC/ENTR" to move onto the next parameter, or the “STATUS” button to exitfunction 36 without saving any updated settings.

3.24.6 Pressing "FUNC/ENTR" on “Display/Setup IP Address” allows the user to view and/orchange the IP Address of the NTS-100 unit. The format of the IP Address display isshown here:

IP Address:255.054.000.034 (Example)

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3.24.7 The Left and Right arrow keys move the cursor beneath the digits of the address. TheUp and Down arrow keys or the number keys can be used to modify the address. Uponcompletion, use the "FUNC/ENTR" key to enter the address shown and proceed to thenext parameter, “CLR” to restore the original setting, or “STATUS” to exit function 36without saving any updated settings.

3.24.8 Pressing "FUNC/ENTR" on “Display/Setup Subnet Mask” allows the user to view and/orchange the Subnet Mask of the NTS-100 unit. The format of the IP Address display isshown here:

Subnet Mask:255.255.255.240 (Example)

3.24.9 The Left and Right arrow keys move the cursor beneath the digits of the mask. The Upand Down arrow keys or the number keys can be used to modify the mask. Uponcompletion, use the "FUNC/ENTR" key to enter the mask shown and proceed to the nextparameter, “CLR” to restore the original setting, or “STATUS” to exit function 36 withoutsaving any updated settings.

3.24.10 Pressing "FUNC/ENTR" on “Display/Setup Default Gateway” allows the user to viewand/or change the Default Gateway of the NTS-100 unit. The format of the DefaultGateway display is shown here:

Default Gateway:255.054.000.033 (Example)

3.24.11 The Left and Right arrow keys move the cursor beneath the digits of the address. TheUp and Down arrow keys or the number keys can be used to modify the address. Uponcompletion, use the "FUNC/ENTR" key to enter the address shown and proceed to thenext parameter, “CLR” to restore the original setting, or “STATUS” to exit function 36without saving any updated settings.

3.24.12 Pressing "FUNC/ENTR" on “Display/Setup Network Type” allows the user to view and/orchange the Network Type of the NTS-100 unit. The format of the Network Type displayis shown here:

Network Type:Ethernet II DIX (Example)

3.24.13 The Up and Down arrow keys toggle the Network Type between “Ethernet II DIX”, and“IEEE 802.3”. When the required type is shown, use the "FUNC/ENTR" key to enter theNetwork Type and proceed to the next parameter, “CLR” to restore the original setting, or“STATUS” to exit function 36 without saving any updated settings.

3.24.14 Pressing "FUNC/ENTR" on “Display/Setup Clock Accuracy” allows the user to viewand/or change the Clock Accuracy of the NTS-100 unit. The format of the ClockAccuracy display is shown here:

Clock Accuracy:1.00e-06 (Example)

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3.24.15 The Left and Right arrow keys move the cursor beneath the digits of the accuracy. TheUp and Down arrow keys or the number keys can be used to modify the value. Uponcompletion, use the "FUNC/ENTR" key to enter the accuracy shown and proceed to thenext parameter, “CLR” to restore the original setting, or “STATUS” to exit function 36without saving any updated settings.

3.24.16 Pressing "FUNC/ENTR" on “Clock Type” advances the display to the “Display EthernetAddress” display if no modifications were made. If any of the parameters were modified,the NTS-100 queries the user about saving the parameters, and, if necessary, rebootingthe NTS-100 unit. . The format of the Clock Type display is shown here:

Clock Type:IRIG (Example)

3.24.17 Press "FUNC/ENTR" to display the Ethernet Address of the NTS-100

3.25 FUNCTION 66 - DAYLIGHT SAVINGS ENABLE3.25.1 Use function 66 to set the Daylight Savings Time entry and exit times. The initial out-of-

the-box default is "Off". The default upon subsequent power-ups will be the selection inuse just prior to the previous power-down.

3.25.2 Press "FUNC/ENTR", then "6" "6". The display will show:Daylight Saving or Daylight SavingOff Manual

3.25.3 Press the up- or down-arrow key to scroll between the choices. When the display showsthe desired choice press "FUNC/ENTR" to enter your choice.

3.25.4 The display and all other time outputs indicate UTC without any DST adjustment if atime-zone offset of 00:00 is selected. Regardless of the time-zone offset there will be noDST adjustment if "Off" is selected for the DST function. Some local jurisdictions enterand leave DST at times other than those set by U.S. federal law. Therefore, TrueTimehas included a "Manual" choice which allows the user to override the times of entry intoand exit from DST by selecting his own. If "Manual" is selected for the DST function, thedisplay will show:

Enter dst: 02:001st Sun in Apr

or some other entry time and date. Press the right- or left-arrow keys to position thecursor beneath the character that you wish to change. Press the up- or down-arrow keysto scroll through the possible choices. Alternatively, directly enter the numbers using thekeypad. The cursor will automatically advance to the next position. The hours mayrange from 0 to 23. The week may be "1st", "2nd", "3rd", "4th", or "Last". Any day of theweek or month may be selected. The above display means that Daylight Savings Timewill start at 2 a.m. local time on the first Sunday in April each year. DST transitions maybe set to occur at any hour of the day, any day of the week or any month of the year withthe following restriction: If either transition is less than 24 hours from the start or end of ayear, the transition may not occur at the desired time.

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3.25.5 When the display shows the desired entry time and date, press "FUNC/ENTR" again,and the display will show:

Leave dst: 02:00Last Sun in Oct

or some other entry time and date. Press the right- or left-arrow keys to position thecursor beneath the character that you wish to change. Press the up- or down-arrow keysto scroll through the possible choices. Alternatively, directly enter the numbers using thekeypad. The cursor will automatically advance to the next position. The ranges are thesame as before but the exit time must be later than the entry time otherwise DST willnever be entered. When the display shows the desired exit time, press "FUNC/ENTR" toenter the selections. The data entry may be aborted at any time prior to pressing the last"FUNC/ENTR" by pressing either the "TIME", "STATUS", or "POSITION" keys.

3.25.6 Once the entry and exit times are entered, they will be retained in nonvolatile memory ifthe clock loses power or is turned off. If the nonvolatile memory is corrupted due tobattery failure or any other cause, the entry time will default to 2:00 a.m. on the firstSunday in April and the exit time will default to 2:00 a.m. on the last Sunday of October.

3.25.7 The sequence of the count upon entry into DST is:01:59:5801:59:5903:00:0003:00:01

assuming the entry time was 2:00 a.m.. The sequence upon exit from DST is:01:59:5801:59:5901:00:0001:00:01

assuming the exit time was 2:00 a.m..3.25.8 If the DST function is enabled or disabled when DST is already in effect, the display will

take several seconds to respond. Each time zone transitions into and out of DaylightSavings Time independently. This means that if the current time zone just entered DSTand the time zone offset is then changed by means of keypad function 01 to a time zonein which the local time of the transition has not yet occurred, the standard time for thatzone will be displayed. If the original time zone setting is restored, its time will remain inDST.

3.26 FUNCTION 67 - LEAP SECOND INFORMATION3.26.1 Though strictly they may be performed at two other times during the year, in practice

UTC leap second adjustments are only performed on two days of the year: June 30 andDecember 31. Use keypad function 67 to retrieve/send information regarding upcomingleap seconds. To return the leap second status, send the string:

3.26.2 Press "FUNC/ENTR", then "6" "7". The display will show:Leap second jump06/30/96 None (Example)

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3.26.3 The NTS-100 will automatically determine the next available date for a leap second. TheUp and Down arrows can be used to scroll between None, +1, and -1. A setting of “+1”will cause a second to be added to the end of June 30, 1996. A setting of “-1” will causea second to be subtracted from the end of June 30, 1996. A setting of “None” will noteffect the time. Press "FUNC/ENTR" to enter the new value, “CLR” to return the originalsetting, or “STATUS” to exit function 67 without changing the previously storedinformation.

3.27 SERIAL I/O INTERFACE3.27.1 The Serial I/O port can be connected to a terminal or computer. It is configured as a

DTE interface and will require a null modem for operation with a terminal or computer. The default factory settings for the Serial I/O port are:

Baud Rate: 9600Parity: EvenData Bits: 7Stop Bits: 1

3.28 SERIAL I/O FUNCTION LISTF01 Time Zone Entry/RequestF02 12/24 Hour ModeF03 Time/Date Entry/RequestF05 Time Quality Enable/SetupF08 Continuous Time Once Per Second EnableF09 Time on Request EnableF11 Time Output Format Entry/RequestF13 Worst-case Time Error RequestF18 Software Version RequestF36 NTS-100 Configuration Entry/RequestF66 Daylight Savings EnableF67 Leap Second Information Entry/Request

3.29 FUNCTION 01 - TIME ZONE ENTRY/REQUEST3.29.1 Use Serial I/O Function F01 to select or determine the time zone offset. To request the

offset send F01<CR> to the Serial I/O port. The port will respond with the followingcharacter string:

F01<SEP><SIGN><HH>:<MM><LT>

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whereF = ASCII character F.01 = function number.<SEP> = one or more separator characters: either space,

comma or tab.SIGN> = either no character or + for positive offsets or - for

negative offsets.<HH> = one or two digit hours offset from +12 to -12 hours. : = ASCII character for a colon.<MM> = two-digit minutes offset.<LT> = line terminator, either a carriage return and line feed

for output strings or a carriage return only for input strings.

Sample request: F01<CR>Response: -4:30<CR><LF>

3.29.2 To set the time zone offset send a character string with the following format:Sample entry: F01 -8:00<CR>Response: OK<CR><LF>

Sample Request: F01<CR>Response: -8:00<CR><LF>

3.30 FUNCTION 02 - 12/24 HOUR FORMAT ENTRY/REQUEST3.30.1 Use Serial I/O function F02 to request or set the time display format. To determine the

format send F02<CR> to the Serial I/O port. The port will respond with the followingcharacter string:

F02<SEP><HH><LT>


comma or tab.<HH> = 12 or 24.<LT> = line terminator, either a carriage return and line feed


Sample request: F02<CR>Response: F02 12<CR><LT>

3.30.2 To select 24 hour format, send the following character string:Sample entry: F02 24<CR>Response: OK<CR><LF>

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3.31 FUNCTION 03 - TIME/DATE ENTRY/REQUEST3.31.1 Use Serial I/O function F03 to enter or request time and date. To request time and date

send F03<CR> to the Serial I/O port. The port will respond with the ASCII characterstring:

F03<SEP><TYPE><SEP><mm>/<dd>/<yy><SEP><HH>:<MM>:<SS><LT>


comma or tab.<TYPE> = either LOCAL or UTC.<mm> = one- or two-digit month./ = ASCII character slash.<dd> = one- or two-digit day.<yy> = two-digit year.<HH> = one- or two-digit hours.: = ASCII character for a colon.<MM> = two-digit minutes.<SS> = two-digit seconds.<LT> = line terminator, either a carriage return and line feed


Sample request: F03<CR>Response: F03 UTC 01/07/91 02:48:29<CR><LF>

Sample entry: F03 LOCAL<CR>Response: F03 LOCAL 01/07/91 7:48:29<CR><LF>

Sample request: F03 UTC<CR>Response: F03 UTC 01/07/91 2:48:29<CR><LF>

3.31.2 To set the time zone offset send a character string with the format above to the Serial I/Oport. Either the date MM/DD/YY or the time HH:MM:SS may be omitted if they arereplaced with a semicolon (;). Only valid dates are acceptable.

3.31.3 The following entry sets the local date and time.Sample entry: F03 LOCAL 10/3/03 20:07:04<CR>Response: OK<CR><LF>

3.31.4 The following entry uses semicolons to omit the time type and date fields, thus settingthe UTC time, and leaving the date unchanged.

Sample entry: F03 ;; 3:06:48<CR>Response: OK<CR><LF>

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3.32 FUNCTION 05 - TIME QUALITY ENABLE/SETUP3.32.1 Use function F05 to enable or disable the time quality indicators or to set the four worst-

case-error thresholds. The Serial I/O output string indicates the time quality. Refer to"SERIAL I/O FUNCTION F08 - CONTINUOUS TIME ONCE PER SECOND" for adescription of the time quality indication in the Serial I/O time output string. As shippedthe time quality indicators are enabled and the thresholds are set to 10000ns, 100000ns,1000000ns and 10000000ns. The unit will retain the values in use at power-down anduse them for subsequent power-ups.

3.32.2 To determine if the indicators are enabled and what the thresholds are, send F05<CR>to the Serial I/O port. The port will respond with the ASCII character string

F05<SEP><STATE><SEP><FLAG><SEP><FLAG><SEP><FLAG><SEP><FLAG><LT>

whereF = SCII character F.05 = function number.<SEP> = one or more separator characters: either space,

comma or tab.<STATE> = ON or OFF.<FLAG> = one error threshold in nanoseconds, 1 to 11 digits

with or without leading zeros.<LT> = line terminator, either a carriage return and line

feed for output strings or a carriage return only for input strings.

Sample request: F05<CR>Response: F05 ON 00000000100 00000001000 00000010000

00000020000

3.32.3 To enable, disable or set the thresholds of the time quality indicators send a characterstring with the following format:

Sample: F05 ON 00000000100 00000001000 0000001000000000020000

Response: OK<CR><LF>

3.32.4 Acceptable threshold value range: 00000000010ns to 40000000000ns.Sample entry: F05 ON 100 200 500 1000Response: OK<CR><LF>

3.32.5 Note that although leading zeros are not required for data entry they will be included inany data response.

3.33 FUNCTION 08 - CONTINUOUS TIME ONCE PER SECOND ENABLE3.33.1 Internal time will output once per second at the Serial I/O port if command string

F08<CR> is sent to the port. Time-of-year will output once per second after time inputvia function F03. Character transmission is continuous with the end of the stop bit of onecharacter coinciding with the beginning of the start bit of the next character. The time

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output string format may be changed with Serial I/O Function F11. The default outputstring format is:

<SOH>DDD:HH:MM:SSQ<CR><LF>

where<SOH> = ASCII Start-of-Header character (HEX 01).<CR> = ASCII Carriage Return character (HEX 0D).<LF> = ASCII Line Feed character (HEX 0A).DDD = day-of-year.HH = hours.MM = minutes.SS = seconds.: = colon separator.Q = time quality character.

The time quality character may be a:

SPACE which indicates a worst-case error less thanthreshold 1.

. which indicates a worst-case error greater than orequal to threshold 1

* which indicates a worst-case error greater than orequal to threshold 2.

# which indicates a worst-case error greater than orequal to threshold 3.

? which indicates a worst-case error greater than orequal to threshold 4.

3.33.2 Refer to serial I/O function 13 - WORST-CASE-TIME ERROR REQUEST. The carriagereturn character <CR> start bit begins on the second, +0 to +1 bit time or ±1 ms, whichever is larger. Time will continue to output once per second until the port receives aCONTROL-C character (HEX 03). Until it receives a CONTROL-C the port will ignore allother input.

3.34 FUNCTION 09 - TIME ON REQUEST ENABLE3.34.1 When the Serial I/O port receives the command string F09<CR> it waits for a request in

the form of an upper-case ASCII character T to output the time-of-day string. After a T isreceived, the current time is saved (with a resolution of 1ms) in a buffer and is thentransmitted to the port. The port will continue to respond with time-of-day each time itreceives a T until this function is canceled by sending a CONTROL-C character (HEX03) to the port (all other input will be ignored until then). The default output string is asfollows:

<SOH>DDD:HH:MM:SS.mmmQ<CR><LF>

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where<SOH> = ASCII Start-of-Header character (HEX 01)<CR> = ASCII Carriage Return character (HEX 0D)<LF> = ASCII Line Feed character (HEX 0A)DDD = day-of-yearHH = hoursMM = minutesSS = secondsmmm = milliseconds: = colon separatorQ = time quality character. Refer to Function 08 for

values

Sample entry: F09<CR>Second entry: TResponse: <SOH>128:20:30:04.357*<CR><LF>

3.35 FUNCTION 11 - TIME OUTPUT FORMAT ENTRY/REQUEST3.35.1 Use Serial I/O Function 11 to request or enter the time output string format that is used

by Serial I/O Functions F08 and F09.3.35.2 The format upon power-up will be the format that was in use just before power-down. To

request the return of the present format send F11<CR> to the Serial I/O port. The stringreturned will contain X's in the positions that are omitted in the time output string.

3.35.3 When shipped, the format string will be set to the "null" string, causing the strings of theF08 and F09 outputs to take on their default values.

F08: <SOH>DDD:HH:MM:SSQ<CR><LF>(Once per second time output mode)

Note: Milliseconds are never present in the output of F08 mode regardless of theformat string entered with F11.

F09: <SOH>DDD:HH:MM:SS.mmmQ<CR><LF>(Time on demand output mode)

where<SOH> = ASCII Start-of-Header character (HEX 01)<CR> = ASCII Carriage Return character (HEX 0D)<LF> = ASCII Line Feed character (HEX OA)DDD = day-of-yearHH = hoursMM = minutesSS = seconds. = ASCII decimal pointmmm = milliseconds: = colon separatorQ = time quality character. Refer to Function 08 for

values.

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3.35.4 If non-volatile memory is corrupted the format string will be set to the "null" string.3.35.5 When the unit returns the current format string in response to "F11<CR>" (as shown in

the following example) the first character after the "F11" is always a blank and is not partof the format string but is only a separator.

Sample request: F11<CR>Response: F11 <CR><LF>

The following text assumes that the format has been previously set to DDD::MMmSSQ.Sample request: F11<CR>Response: F11 DDD:XX:MMmSSXXXXQ<CR><LF>

3.35.6 This means that the response from F09 would be:<SOH>122::24m55*<CR><LF>

3.35.7 To omit a character, other than <SOH> <CR> or <LF>, from the output string send astring of the form:

F11<SEP>DDD:HH:MM:SS.mmmQ<CR>

3.35.8 An upper case "X" should be used in place of the character(s) that you wish to omit. The<SOH>, <CR> and <LF> characters in the output strings of F08 and F09 are not subjectto control by F11. <SEP> is one character only, either a space, comma or tab. Anycharacter other than an upper case "X" in a numeric position will not affect the output ofthat position. The colons (:) or decimal point (.) , however, may be replaced with anysingle ASCII character except null (HEX 00), carriage return, or line feed.

Sample entry: F11 XXXXXXXMMMSSS.mmmX<CR>Response: OK<CR>F08 string output: <SOH>12M34S<CR><LF>F09 string output: <SOH>12M34S.567<CR><LF>

3.35.9 The above format means that days hours and the first two colon separators aresuppressed and the third and fourth separators are "M" and "S".

Sample entry: F11,HHH;XX;mm:SS,mmmQ<CR>Response: OK<CR>F08 string output: <SOH>123;;55:45*<CR><LF>F09 string output: <SOH>123;;55:45,678*<CR><LF>

3.35.10 The above format means that hours are deleted, the first two separators are semicolonsinstead of colons and the third separator is a comma instead of a period.

3.35.11 If the format string entered with F11 is terminated early with a carriage return, theremaining characters are enabled and assume their default values.

Sample entry: F11<TAB>XXX|<CR>Response: OK<CR>F08 string output: <SOH>|10:45:01*<CR><LF>F09 string output: <SOH>|10:45:01.234*<CR><LF>

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3.35.12 The above format means that days are deleted, the first separator is a vertical bar and allother characters are enabled and assume their default values.

3.35.13 When entering a new format string the character after "F11" is required but is ignored.To enter a "null" format string send "F11" followed by a space, followed by a carriagereturn.

Sample entry: F11 <CR>Response: OK<CR>F08 string output: <SOH>DDD:HH:MM:SSQ<CR><LF>F09 string output: <SOH>DDD:HH:MM:SS.mmmQ<CR><LF>

3.35.14 The above format means that all characters and separators are enabled and assumetheir default values.

3.35.15 If the current format string is "null", F11 will return a space character followed by acarriage return.

Sample entry: F11<CR>Response: F11 <CR>

3.35.16 The format string below explicitly enables all characters and has the same effect as a"null" format string:

Sample entry: F11 DDD:HH:MM:SS.mmmQ<CR>Response: OK<CR>F08 string output: <SOH>DDD:HH:MM:SSQ<CR><LF>F09 string output: <SOH>DDD:HH:MM:SS.mmmQ<CR><LF>

3.36 FUNCTION 13 - WORST-CASE TIME ERROR REQUEST3.36.1 Use Serial I/O Function F13 to request the estimated worst-case time error. Refer to

keypad FUNCTION 13 - WORST-CASE TIME ERROR earlier in this Section for anexplanation of worst-case time error. The worst-case time error while thesynchronization source input is present and the NTS-100 is locked to it depends uponthe type of synchronization source. Refer to Section 5 for the timing accuracyspecification for your synchronization source option. Time error begins to accumulatewhen the NTS-100 loses the synchronization source. The NTS-100 calculates the worst-case time error based on the stability of the time base and the time elapsed since loss ofsynchronization source. The Serial I/O port will report this calculated error when itreceives the string F13<CR> and responds with the following ASCII character string:

F13<SEP><ERROR><CR><LF>

whereF = ASCII character F.13 = function number.<SEP> = one or more separator characters; either space,

comma or tab.<ERROR> = calculated worst-case error in seconds<CR> = carriage return character. <LF> = line feed character.

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Sample request: F13<CR>Response: F13 02.000000000<CR><LF>

3.37 FUNCTION 18 - SOFTWARE VERSION REQUEST3.37.1 Use Serial I/O Function F18 to obtain information about the current version of the

software installed in the unit. Send the string:F18<CR>

3.37.2 The unit will respond with a string no longer that 80 characters, such as:TRUETIME Mk III sys ver 001 NTS V1.000 182-7002v001<CR><LF>

3.37.3 This string indicates that the system software is version 001, the Network Time Server-specific software is version 1.000 and the specific EPROM image is 182-7002, version001.

3.38 FUNCTION 36 - NTS-100 CONFIGURATION ENTRY/REQUEST3.38.1 Use Serial I/O Function F36 to obtain information about the current NTS-100

configuration or to change the setup. Changing the network related fields of theconfiguration will cause a reset of the NTS-100 module.

Ethernet Address3.38.2 The ethernet address is a six byte, hexadecimal value specific to each NTS-100 module.

The first three bytes are registered to TrueTime Inc, and the last three bytes are the hexvalue of the unit’s unique number. The ethernet address of the NTS-100 is a fixedaddress established at the factory. To request the ethernet address of the NTS-100module, send the string:

F36 EA<CR>

3.38.3 The unit will respond with:F36 EA:00-A0-69-xx-xx-xx<CR><LF>

where “xx-xx-xx” are the six hex digits of the unit’s unique address. Attempts to setthis field will be rejected with a syntax error message.

IP Address3.38.4 To obtain the IP address of the NTS-100 module, send the string:

F36 IP<CR>

3.38.5 The unit will respond with a string of the form:F36 IP:nnn.nnn.nnn.nnn<CR><LF>

where “nnn.nnn.nnn.nnn” is the dotted decimal address notation. To set the IP addressand restart the NTS-100, send a string of the form:

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F36 IP:nnn.nnn.nnn.nnn<CR>F36 IP:206.54.0.21<CR> (Example)

Changing this parameter will cause a software reset of the NTS-100 module.

Subnet Mask3.38.6 To return the subnet mask of the NTS-100 module, send the string:

F36 SM<CR>

3.38.7 The unit will respond with:F36 SM:nnn.nnn.nnn.nnn<CR><LF>

3.38.8 To set the subnet mask and restart the NTS-100, send the string:F36 SM:nnn.nnn.nnn.nnn<CR>F36 SM:255.255.255.240<CR> (Example)


Default Gateway3.38.9 To obtain the default gateway of the NTS-100 module, send the string:

F36 G<CR>

3.38.10 The unit will respond with:F36 G:nnn.nnn.nnn.nnn<CR><LF>

3.38.11 To set the default gateway and restart the NTS-100, send the string:F36 G:nnn.nnn.nnn.nnn<CR>F36 G:206.54.0.17<CR> (Example)


Network Packet Type3.38.12 To determine the type of network packets being used, send the string

F36 N<CR>

3.38.13 The unit will respond with one of two strings.F36 N:I<CR><LF> For IEEE 802.3 networksorF36 N:E<CR><LF> For Ethernet II DIX networks

3.38.14 To set the type of network being used send the appropriate string shown below.F36 N:I<CR> For IEEE 802.3 networks F36 N:E<CR> For Ethernet II DIX

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3.38.15 Note that this setting affects only the packet type that the NTS-100 will transmit. TheNTS-100 will receive packets of either type, regardless of this setting.Changing this parameter will cause a software reset of the NTS-100 module.

Complete NTS-100 Network Configuration3.38.16 To review the entire current network configuration of the NTS-100 module, send the

string:F36<CR>

3.38.17 The unit will respond with (example):F36 IP:206.54.0.21 SM:255.255.255.240 G:206.54.0.17 N:E<CR><LF>

3.38.18 This response indicates the specific IP address, Subnet Mask, Default Gateway, andNetwork Type of the NTS-100 module. Note that the leading zeros within fields of thedotted decimal addresses are omitted from the IP address, Subnet Mask, and DefaultGateway.

3.38.19 To set all settable network parameters and reset the NTS-100 card, send the string(example):

F36 IP:206.54.0.21 SM:255.255.255.240 G:206.54.0.17 N:E<CR>

3.38.20 This example provides the NTS-100 card with an IP address, Subnet Mask, DefaultGateway and Network Type. Note that leading zeros may be omitted when entering IPaddress, Subnet Mask, and Default Gateway. Any field may be omitted and order is notsignificant. Blanks are allowed on either side of a colon. Any legal command setcontaining one of the four network parameters will cause a software reset of theNTS-100.

Clock Type3.38.21 The synchronization input option determines the clock type. To query the clock type,

send the string:F36 T<CR>

3.38.22 The unit will respond with:F36 T:GPS<CR><LF> For GPS unitsF36 T:IRIG<CR><LF> For IRIG B unitsF36 T:1PPS<CR><LF> For External 1 PPS unitsF36 T:ACTS<CR><LF> For ACTS units

3.38.23 Attempts to set this field will be rejected with a syntax error message.

Clock Accuracy3.38.24 When the synchronization input option of the NTS-100 is either IRIG-B or External 1PPS,

the accuracy of the timing source driving the IRIG-B or External 1PPS input must beprovided to the NTS-100 so that the appropriate fields in the NTP packet may be

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properly set. To obtain the current setting of the accuracy of the local time source, sendthe string:

F36 A<CR>

3.38.25 The unit will respond with (example):F36 A:1.0e-5<CR><LF>

This example illustrates a unit with an accuracy of 10 µs.

3.38.26 To set the accuracy of the NTS-100 module, send the string (example):F36 A:0.5e-3<CR>

This example illustrates setting the accuracy of the NTS-100 module to 0.5 ms.

3.38.27 When the synchronization input option is GPS, the NTS-100 will automatically make thissetting, and operator attempts to set it will be ignored.

3.39 FUNCTION 66 - DAYLIGHT SAVINGS ENABLE3.39.1 Use Serial I/O Function F66 to enable or disable or set the entry or exit times for DST.

The initial out-of-the-box default is "Off". The default upon subsequent power-ups willbe the selection in use just prior to the previous power-down.

3.39.2 To request the present status of the daylight savings enable, send F66<CR> to the serialport. The port will respond with the ASCII character string:

F66<SEP><STATE><LT>

whereF = ASCII character F.66 = function number<SEP> = one or more separator characters: either space,

comma or tab.<STATE> = Off or Manual.<LT> = line terminator, either a carriage return and line feed


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3.39.3 If the DST function is in Manual, the port will respond with the longer string describedbelow.

Sample request: F66<CR>Response: F66 OFF<CR><LF>

3.39.4 To alter the state of the daylight savings enable send a character string with the formatabove to the serial port.

Sample entry: F66<TAB>Off<CR>Response: OK<CR><LF>

3.39.5 To place the DST function in Manual and set the DST entry and exit times send acontinuous string of the form:

F66 MANUAL <IN HOUR><SEP><IN WEEK><SEP><IN DAY><SEP><INMONTH><OUT HOUR><SEP><OUT WEEK><SEP><OUT DAY><SEP><OUTMONTH><LT>

where<IN HOUR> = time to enter DST in 24-hour format.<SEP> = one or more separator characters, either space

comma or tab characters. For output strings this will be a single space character.

<IN WEEK> = which week to enter DST, 1, 2, 3, 4 or 0 (for last).<IN DAY> = day of week to enter DST, 1 through 7 where

Sunday is 1.<IN MONTH> = month to enter DST, 1 through 12 where 1 is

January.<OUT HOUR> = hour to exit DST, in 24 hour format.<OUT WEEK> = which week to exit DST, 1, 2, 3, 4 or 0 (for last).<OUT DAY> = day in to exit DST, 1 through 7 where Sunday is 1.<OUT MONTH> = month to exit DST, 1 through 12 where 1 is January<LT> = line terminator, a carriage return and line feed for

output strings, only a carriage return for input strings.

3.39.6 If desired, any item may be replaced with a semicolon, which will leave its valueunchanged. If any of the items in an input string are invalid, an error message will bereturned.

Sample Request: F66<CR>Response: F66 MANUAL 02 1 1 04 02 0 1 10Meaning: Manual settings are in effect. The entry time is 02 a.m.

on the first Sunday of April and the exit time is 02 a.m.on the last Sunday in October.

Sample Entry: F66 MANUAL ; 0 ; ; ; ; ; ;<CR>Response: OK<CR><LF>Meaning: DST will now be entered on the last week of the

month. All other parameters remain unchanged.

Sample Entry: F66 MANUAL 4 2 2 3 13 4 6 11<CR>

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Response: OK<CR><LF>Meaning: DST will now be entered 04 a.m. on the 2nd Monday in

March and exit DST at 01 p.m. on the 4th Friday inNovember.

3.40 FUNCTION 67 - LEAP SECOND INFORMATION3.40.1 Though strictly they may be performed at two other times during the year, in practice

UTC leap second adjustments are only performed on two days of the year: June 30 andDecember 31. Use serial function 67 to retrieve/send information regarding upcomingleap seconds. To return the leap second status, send the string:

F67<CR>

3.40.2 The NTS-100 module will return:F67 06-30-96 +1<CR><LF>

3.40.3 This response indicates a leap second addition during the last minute of June 30, 1996. If there is no leap second pending, the module will return:

F67 none<CR><LF>

3.40.4 To set the leap second information for the next possible adjustment date, send thefollowing strings:

F67 06-30-96 +<CR> To set a leap second addition for June 30, 1996F67 12-31-98 -1<CR> To set a leap second subtraction for Dec. 31, 1998F67 none<CR> To clear the leap second setting.

3.40.5 If a date for a leap second event is sent other than the next possible adjustment date, i.e.June 30 if the current date is in the first half of the year or December 31 if the currentdate is in the second half of the year, the NTS-100 will return an error message andignore the information.

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NNTTSS--220011--MMAANN 44--11 RReevv.. AA

4.

SECTION IVNOT USED

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5. ace Marker

SECTION VIRIG B SYNCHRONIZATION OPTION

5.1 IRIG B SETUP AND OPERATION5.1.1 This Section describes setup and operating procedures for using the NTS-100 with IRIG

B as the synchronization source.5.1.2 The NTS-100 IRIG-B Sync Input characteristics are:

Format: IRIG-BInput Range: 0.5 Vpp to 5.0 VppInput Z: 10 KΩAccuracy: ± 5 µs, with respect to the input code

5.1.3 After making the appropriate input connection and applying power, the Serial I/O port orfront panel keypad must be used to continue setup of the NTS-100.

5.1.4 Since IRIG B does not contain year information, the date must be set using Function 03.Function 03 is described in detail in Section 3. To set the date via the Serial I/O port,send the string:

F03 UTC MM/DD/YY ;<CR>or, to set the date via the front panel keypad:

5.1.5 Press "FUNC/ENTR" “0” “3” "FUNC/ENTR", use the keypad to enter the date, then press"FUNC/ENTR", use the keypad to enter the approximate time, then press "FUNC/ENTR".

5.1.6 Using Serial I/O F03 in this manner does not affect the time. Only after the date hasbeen entered will the NTS-100 indicate a lock to the incoming IRIG B time code, andrespond to NTP packet requests with the Leap Indicator bits set to a value other than 3,the alarm condition.

5.1.7 Although it is not absolutely necessary to provide leap second information to theNTS-100 with IRIG-B synchronization option, if it is not provided there are two potentialdrawbacks: • The NTS-100 will not place any advance indication in the Leap Indicator field of the

NTP packet of an impending leap second event. Refer to Appendix A for details ofthe NTP packet format.

• There will be a short period at and following the occurrence of the leap second eventduring which the NTS-100 time will disagree with the IRIG-B synchronization source(assuming that the IRIG-B source is maintaining strict UTC). This will only persistuntil the NTS-100 has determined that a valid time step of the input IRIG-B hasoccurred (a few seconds) and corrects its time to match the IRIG-B source. Duringthis period, NTP packet timestamps created by the NTS-100 will be in error.

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5.1.8 During the six months prior to the addition of a new leap second, the USNO will publishto the user community its plan to implement a leap second. Leap seconds are added (orsubtracted) only at the end of the days of June 30 and December 31. If the NTS-100 isinformed of an impending leap second adjustment at any time during the six months priorto the next leap second adjustment, then it will store that information in its EEPROM. When the time for the leap second adjustment approaches, the NTS-100 willautomatically place the appropriate information in the Leap Indicator field of the NTPpacket and at the appropriate time will perform the leap second correction to its internalclock. Use Serial I/O Function F67, which is described in detail in Section 3, to providethis information to the NTS-100.

5.1.9 When operating the NTS-100 from an IRIG-B synchronization source, the operator mustinput information about the clock which is producing the IRIG-B signal. The parameterwhich is required is entered using the Serial I/O Function F36 and is the “ClockAccuracy” field. This field must specify the accuracy of the clock which is being used togenerate the IRIG-B code. Refer to Section 3, Function F36 and Appendix A for moredetail on the setting of this parameter.

5.1.10 In addition, if the incoming IRIG-B sync input contains embedded Lock Quality indicatorsthen the operation of the NTS-100 with respect to these must be configured via Function36:

F36 Keypad Operation:

5.1.11 Pressing "FUNC/ENTR" on “Display/Setup IRIG Lock Quality” enables the user to viewand/or change the bit in the IRIG code which determines the status of the NTS-100 lockindicators. The format of the IRIG Lock Quality display is shown here:

IRIG-B LockQuality: Lock (Example)

5.1.12 Pressing the Up and Down arrows scrolls through the selections for Lock Quality: Lock,TQ1, TQ2, TQ3, TQ4, and None. When the desired selection is displayed, press"FUNC/ENTR" to enter the selection and proceed to the next parameter, “CLR” to restorethe original setting, or “STATUS” to exit function 36 without saving any updated settings.

F36 Serial I/O Operation:

5.1.13 The IRIG Lock Quality determines the bit in the incoming IRIG data which the NTS-100uses to determine whether or not it is receiving valid time. Possible settings are: Lock,TQ1, TQ2, TQ3, TQ4, and None. To determine the current configuration of theNTS-100, send the string:

F36 IQ<CR><LF>

5.1.14 The unit will respond with:F36 IQ: setting

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5.1.15 To set the IRIG Lock Quality, send a string of the form:F36 IQ: setting<CR><LF>

5.1.16 F36 IQ: None<CR><LF> (Example)

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SECTION VI6.

MD5 AUTHENTICATION PROTOCOL

6.1 MD5 INTRODUCTION6.1.1 MD5 is a security protocol that can be used to authenticate NTP client - server

communications. TrueTime’s version of MD5 is completely compatible with currentversions of NTP client software xntpd 3.XX and ntpdate 3.XX furnished by Dr. David Millsat the University of Delaware. MD5 was drafted into a standard by MIT Laboratory forComputer Science and RSA Data Security, Inc. MD5 authentication means theinformation within the NTP packet is guaranteed to be unaltered and from a user havingprivileged access. Unlike other cryptographic ciphers, MD5 does not hide the data withinthe packet. The MD5 authenticated NTP packet is still readable. This means MD5 isfaster to generate than other cryptographic protocols, and as Dr. Mills notes, there is noreason to hide the actual time from anyone. Further, MD5 does not suffer from anyexport restrictions. Think of MD5 as a very sophisticated NTP data checksum that isextremely difficult to reverse generate.

6.1.2 The MD5 cryptographic key identifier and cryptographic message digest are tacked on tothe end of a normal NTP packet and the two pieces of information are referred togetheras an MD5 signature. The key identifier is the first field in the signature and it is a 32 bitinteger in the range from 1 to 4294967295 (0xFFFFFFFF). Note: Zero is an illegalvalue, and for TrueTime setup purposes, 0 internally means the key identification isunused. This number specifies an index into a table of many possible MD5 keys. A keyis an ASCII alpha/numeric character string that is from 1 to 31 characters in length. Thekey is most secure when all 31 characters are filled with numbers and letters chosen atrandom. The ASCII key string is combined with the NTP packet data and results in asecure message digest. The MD5 message digest is 16 bytes in length and it follows thekey identifier in the signature. A server authenticates the NTP packet from a client bylooking up the key by reference to the key identifier; generates the MD5 message digestbased on the key and the NTP data; and compares the resulting message digest to theclient packet’s MD5 message digest. If the two compare, a NTP reply packet isgenerated with a new MD5 signature. If the MD5 message digests do not agree, thenthe NTP client packet is ignored by the TrueTime server.

6.1.3 For more technical information on MD5 see the MD5 RFC 1321, NTP RFC 1305, and therelease notes for NTP client software furnished by Dr. David Mills’ web site located at theUniversity of Delaware at http://www.eecis.udel.edu/~ntp, or http://www.eecis.udel.edu/~ntp/software.html.

6.2 TRUETIME NTP MD5 OPERATION6.2.1 A TrueTime NTP time server can handle both unauthenticated and MD5 authenticated

packets at the same time. A packet is assumed to be MD5 authenticated if the total UDPdata size of the packet is equal to the size of a normal NTP packet plus the exact size ofan MD5 signature. A normal unauthenticated NTP packet is one that has no extra bytesbeyond the last NTP timestamp. The procedure used is functionally the one followed byDr. David Mills’ NTP software. Packets without authentication are returned withoutsignatures and packets with authentication are returned with authentication signature

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using the key ID specified by the client request. If a packet does not send the correctauthentication signature, it is silently dropped.

6.2.2 A TrueTime NTS can contain up to 16 MD5 authentication keys. MD5 keys are enteredand maintained through the standard TrueTime keypad and serial interfaces. Therefore,for security reasons, the TrueTime time server must be physically isolated fromunauthorized users. MD5 keys must be changed on a regular schedule as a furthersecurity measure. Persons privileged to carry and maintain keys must have appropriateclearances and be trained for handling secure information. Note: Keys that are nolonger trusted (are potentially compromised) must be deleted from the TrueTime MD5key table.

6.3 KEYPAD MD5 CONFIGURATION6.3.1 To configure NTP MD5 from the keypad, press the status function button first and then

press FUNC/ENTR 36. This takes you to the network configuration menu. Continuepressing the up-arrow key until the Display/Set NTP MD5 Auth prompt is displayed. Press FUNC/ENTR to start configuration for NTP MD5. This takes you to the menu titledMD5 Main Menu:. There are three menu choices from this menu: 1) Modify MD5 keys,2) Output On/off, and 3) Back one menu. Note for all TrueTime menus: the up anddown arrow keys scroll through the list of menu items and FUNC/ENTR actuates theselected menu option.

6.3.2 Pressing FUNC/ENTR for the Modify MD5 keys option takes you to the menu where youmay edit MD5 keys (or view them). Output On/off specifies a menu where you canenable NTP MD5 authentication for NTP packets broadcast by the TrueTime time server. Note: At this time, NTP broadcast is not yet available and this menu serves no usefulpurpose until that time. The Back one menu choice returns to the previous menu.

6.3.3 Pressing the Modify MD5 keys menu takes you to the MD5 Edit Menu:. In this menu youmay choose: 1) Edit a Key, 2) Add a Key, 3) Delete a Key, 4) Delete all Keys, or 5) Backone menu. If you press Edit a Key, then you will be able to scroll through the list of allcurrently entered MD5 keys and up to sixteen key identifiers can be stored in sortednumerical order, plus a Back one menu entry that will take you to the Modify MD5 keysmenu. Pressing FUNC/ENTR on a particular key identifier takes you to the promptENTER MD5 key up to 31 ASCII char. Pressing FUNC/ENTR again displays the currentvalue of the MD5 key. You may use the up and down arrows to select the charactervalue at a position in the MD5 string and the left and right arrows move to other characterpositions. Note: It is easier to edit the MD5 keys using the serial command. PressingFUNC/ENTR accepts any changes and takes you to the Save key edit? prompt. Next,use the up and down arrows to select Yes or No and FUNC/ENTR to activate thecommand. Note: you can use the edit function to just view MD5 keys and select Nowhen asked to save the key changes. Pressing Yes or No takes you back to the MD5Edit a Key: menu and pressing Back one menu takes you back to the MD5 Edit Menu:.

6.3.4 In the MD5 Edit Menu:, selecting Add a key takes you to the menu where you may add anew MD5 key. Your first prompt is Enter Key ID: followed by the default value of0000000001. You may edit the key ID in the range from 1 to 4294967295. PressFUNC/ENTR and when you finish with the key ID, you will see the MD5 key up to 31ASCII char prompt. Press FUNC/ENTR again and you can enter the actual MD5 key asyou would in the edit menu. Press FUNC/ENTR when done and you are taken to theprompt Add this key?. Select Yes or No in the same way you did for the edit menu andyou can return to the MD5 Edit Menu: by pressing the Back one menu option. Note:

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Entering a key identification that is already in use effectively edits that key to the newvalue. Further note: The key list can have up to 16 MD5 keys.

6.3.5 Back in the MD5 Edit Menu: you can select Delete a key or Delete all keys to removeone or all MD5 keys. These menus operate in a similar fashion as the edit and addmenus and they are protected from accidental entry by yes or no menu confirmations. Further, you will not be allowed to enter these menus if there are no MD5 keys.

6.3.6 When you finish with the MD5 key tasks, you may leave the MD5 menus by successivelypressing Back one menu or by pressing the STATUS key. Note: If you press theSTATUS key, make sure that you have confirmed your last operation in the Yes or Nomenu appropriate for the operation, otherwise your last operation will have no effect.

6.4 SERIAL MD5 KEY CONFIGURATION6.4.1 The easiest method to maintain NTP MD5 keys is through the serial interface. This is

due to the fact that MD5 keys are alpha/numeric strings and the keypad interface doesnot allow easy entry of alpha characters. You may add, delete and view the MD5 keysusing the serial interface.

6.4.2 To view a particular NTP MD5 key type:F36 MV:xWhere x is the key identification number ranging from 1 to 4294967295.

6.4.3 The unit will respond with:F36 key ID = x, key = ValueOfMD5KeyString

6.4.4 To view the next NTP MD5 Key type:F36 MV

6.4.5 The unit will respond with:F36 key ID = (x+1), key = ValueOfMD5KeyStringWhere (x+1) is the next key identification in numerical order from the last serialcommand that reference a key identification. Note: After booting,: the key viewedwill be the lowest numbered key identification. If the previous key viewed was at theend of the key identification list it will wrap back to the first key identification.

6.4.6 To add a NTP MD5 key type:F36 MS:x ValueOfMD5KeyStringWhere x is the key identification number ranging from 1 to 4294967295 andValueOfMD5KeyString is the MD5 ASCII string key ranging from 1 to 31 characters. Note: It is best to limit the string to alpha/numeric characters only. If othercharacters are desired, then the restrictions the remote NTP client program placeson the string must be considered.

6.4.7 The unit will respond with:OK

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6.4.8 To delete a NTP MD5 key type:F36 MD:x

Where x is the key identification number ranging from 1 to 4294967295. The unitwill respond with:

OK

6.4.9 To delete all NTP MD5 Keys type:F36 MD:ALL

6.4.10 The unit will respond with:OK

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SECTION VII7.

SIMPLE NETWORK MANAGEMENT PROTOCOL

7.1 SNMP INTRODUCTION7.1.1 The TrueTime Network Time Server completely supports a SNMP version 1 agent with

the MIB II database. SNMP management software allows a network user to remotelymonitor and configure an IP (Internet) host that supports a SNMP agent. A SNMP agentis protected from unauthorized use through a security authentication scheme. Further,TrueTime has extended the MIB II database with its own custom enterprise MIB thatallows a manager more control than what is specified in the MIB II database.

7.1.2 We assume the reader has an understanding of SNMP because a complete introductionto SNMP would fill many volumes of user manuals. If the reader is unfamiliar withSNMP, pick up a copy of "SNMP, SNMPv2 and CMIP" written by William Stallings andpublished by Addison-Wesley Publishing Company. This book is considered by theInternet community to be the definitive introduction to SNMP. For more technicalreferences, see RFC 1157 (definition of SNMPv1), RFC 1213 (definition of MIB II) andRFC 1354 (IP Forwarding table addition to MIB II). All RFCs are published with approvalby the Internet Activities Board and they are readily found on the Internet by running anysearch engine and typing in the search field “RFC ####”. Some example WEB locationsof search engines are http://search.yahoo.com or http://www.altavista.digital.com.

7.2 SNMP CONFIGURATION7.2.1 SNMP offers a security authentication scheme that is based on a common password

shared by the management station and a group of agents. A group of hosts are knownas a community. Any management station or agent can be a member of anycombination of communities. Typically a manager will need to change the SNMPcommunity information from TrueTime’s SNMP agent factory defaults for securitypurposes. However, the factory default SNMP community settings are chosen to makethe TrueTime SNMP immediately useable. TrueTime’s SNMP agent recognizes up tofive separate SNMP communities. These communities are configured through the serialuser port using the F36 string, the front panel keypad, or in the near future remotelyusing SNMP and TrueTime’s Enterprise MIB. Each community has several configurableparameters that are defined in the following table:

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Key word(as seen from the front panel

display) DefinitionCommunity Name The name of this community. The name is limited to up

to 32 ASCII letters, numbers or punctuation letters. Thisis the name that a management SNMP PDU (packet)specifies. If the community name of an incoming PDUdoes not match any of the five community names, thepacket is ignored and an optional authentication trapmessage can be generated. See traps below. An emptystring field disables the community name.

Trusted IP Address If the Use Trusted IP flag is set to yes, then this is thetable of IP host addresses that this communityrecognizes as valid SNMP management hosts. Even ifthe community name of an incoming PDU matches thiscommunity, the source IP address must match one ofthe IP addresses in this table, or the packet is ignoredand an optional authentication error trap message isissued. Setting an IP address to all zeros turns off thatIP address entry. In addition, this table also serves asthe list of hosts that SNMP trap messages are sent to -no matter what the state of Use Trusted IP flag is.

Use Trusted IP If this flag is set to yes, then the Trusted IP Addresstable is used in addition to the Community Name forauthentication of incoming PDU(s).

R/W Access For a particular community, the SNMP variables are setto read only, or normal SNMP access. This allows themanager to have a public known community from whichanyone may read the SNMP data base and a separateprivate community that has full normal read and writeaccess to the SNMP database. Note: SNMP MIB II doesnot define all variables to be writeable. SNMP variablesdefined by RFC 1213 as read-only remain read-only nomatter what the state of this R/W Access flag is.

Trap Enable When this flag is set to yes, trap messages are issuedfor this community. Note: this enables/disables all traps(both coldstart and authentication).

Trap Port A trap port other than the normal SNMP trap port of 162maybe specified. Note: this address must be chosencarefully, or conflicts with other protocols may occur.

Save settings When any setting is changed, this becomes visible andanswering yes immediately saves the changes toTrueTime’s SNMP. Answering No will negate thechanges.

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7.2.2 The following table defines SNMP configurable parameters that are applied globally to allSNMP communities; this menu appears after the last community menu:

Key word(as seen from the front panel

display) DefinitionSNMP Global Enable Traps When set to yes, all authentication failure traps are

disabled. This flag overrides the Trap Enable flag set foreach community. Note: this directly sets the value of theSNMP variable snmpEnableAuthenTraps.0. Note: thestate of this flag has no effect on the issue of coldstarttrap messages.

Return To Main Menu This leads back to the main SNMP function window.Save settings When SNMP Global Enable Traps is changed, this

becomes visible and answering yes immediately savesthe change to TrueTime’s SNMP. Answering No willnegate the change.

7.2.3 The following table summarizes the TrueTime factory default settings for SNMP:

Key word () DefinitionCommunity 1Community Name publicTrusted IP Address 0.0.0.0, 0.0.0.0, 0.0.0.0, 0.0.0.0Use Trusted IP noR/W Access read/onlyTrap Enable noTrap Port 162Community 2Community Name systemTrusted IP Address 0.0.0.0, 0.0.0.0, 0.0.0.0, 0.0.0.0Use Trusted IP noR/W Access normalTrap Enable noTrap Port 162Community 3 to 5Community NameTrusted IP Address 0.0.0.0, 0.0.0.0, 0.0.0.0, 0.0.0.0Use Trusted IP noR/W Access read/onlyTrap Enable noTrap Port 162SNMP Global Enable Traps yes

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7.2.4 The factory default settings are summarized as follows: community one is called publicand is set to read-only access for the SNMP MIB; community two is named system and ithas normal access to the SNMP database; all other communities are disabled. All trapsare disabled. Many SNMP management utilities are written with these defaultassumptions and thus the TrueTime SNMP is immediately useable without configuration.

7.3 NTP PARAMETERS7.3.1 To configure SNMP from the keypad, press the status function button first and then

press FUNC/ENTR 36. This takes you to the network configuration menu. Continuepressing the up-arrow key until the Display/Set SNMP prompt is displayed. PressFUNC/ENTR to start configuration for SNMP. Next, press the up-arrow to select thecommunity that you want to configure. At the proper SNMP Community menu number,pressing the FUNC/ENTR key takes you into that community and you may configure itsparameters as described in the above tables. Use the up or down arrow keys to togglethrough your settings options. The left and right arrow keys move between digits andletters within an address or a string. Note: because the keypad has only numbers on thefront panel, the letters for community names can only be chosen by using the up or downarrow keys and cycling to the letter of your choice. For this reason, it is more efficient touse the serial port, or the TrueTime Enterprise MIB to set the SNMP community nameparameters.

7.3.2 You may exit the SNMP configuration when you are back in the Display/Set SNMPwindow by pressing the up or down arrow keys. Note: if you use the status key to exitthe SNMP menu you must do this after you have answered yes in the Save settingsmenu or you will loose your settings. Once saved, changes to SNMP take placeimmediately and there is no need to reboot the timeserver.

7.4 SNMP TRUETIME ENTERPRISE MIB VARIABLE DEFINITIONS

The EnterpriseEnterprise OBJECT IDENTIFIER ::= 1.3.6.1.4.1

TrueTime's Enterprise MIBTrueTimeEntMIB OBJECT IDENTIFIER ::= Enterprise 1896

Groups in TrueTime Enterprise MIB:trapMsg OBJECT IDENTIFIER ::= TrueTimeEntMIB 1 ntp OBJECT IDENTIFIER ::= TrueTimeEntMIB 2 ntsControl (Preliminary) OBJECT IDENTIFIER ::= TrueTimeEntMIB 3 gps OBJECT IDENTIFIER ::= TrueTimeEntMIB 4 acts OBJECT IDENTIFIER ::= TrueTimeEntMIB 5

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Display Strings7.4.1 For compatibility with MIB-II definitions

DisplayString ::= OCTET STRING

7.5 THE TRAPMSG GROUP7.5.1 The Implementation of the trapMsg group is mandatory for all TrueTime network

products. The following are the trap messages that are issued by the TrueTime timeserver. Trap messages are issued for cold starts (reboot or power up), NTP loss of timesynchronization and authentication failures for SNMP.

trapMsgColdStart OBJECT-TYPE

SYNTAX DisplayString (SIZE (0..255))ACCESS read-onlySTATUS mandatory

7.5.2 This is an ASCII string sent to UDP port 162 (or user defined) when the TrueTime timeserver reinitializes. The message is "Cold Start Trap PDU from: ###.###.###.###". Where ###.###.###.### is the dotted decimal notation of the IP address of the bootingunit.

::= trapMsg 1

trapMsgNtpAlarm OBJECT-TYPESYNTAX DisplayString (SIZE (0..255))ACCESS read-onlySTATUS mandatory

7.5.3 This is an ASCII string sent to UDP port 162 (or user defined) when the TrueTime timeserver's Leap Indictor is set to 3 (ie ntpSysLeap = 3). This generally means the timeserver has lost primary time synchronization. This could be due to a line breakage in thetiming source, loss of GPS satellites, etc. The message is "NTP Alarm Trap PDU from:###.###.###.###". Where ###.###.###.### is the dotted decimal notation of the IPaddress of the time server in the alarm state. See ntpSyncLeap and ntpSysLeap.

::= trapMsg 2

trapMsgSnmpAuthFail OBJECT-TYPESYNTAX DisplayString (SIZE (0..255))ACCESS read-onlySTATUS mandatory

7.5.4 This is an ASCII string sent to UDP port 162 (or user defined) when the TrueTime timeserver determines the SNMP authentication for a SNMP PDU is in correct. Themessage is "SNMP Authentication Failure Trap PDU from: ###.###.###.###". Where###.###.###.### is the dotted decimal notation of the IP address of the unit attemptingthe invalid access.

::= trapMsg 3

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7.6 THE NTP GROUP7.6.1 The ntp group variables from 1 to 6 are general health variables on the NTP layer and

variables 7 to 14 are culled from Dr. Mills' definition of sys variables in RFC 1305. Note:the NTP variables simplify because the TrueTime units are primary time servers. Variables used directly by NTP packets are provided in their raw forms.

ntpInPkts OBJECT-TYPESYNTAX CounterACCESS read-onlySTATUS mandatory

7.6.2 Total number of NTP packets delivered to the NTP application layer from the transportlayer.

::= ntp 1

ntpOutPkts OBJECT-TYPESYNTAX CounterACCESS read-onlySTATUS mandatory

7.6.3 Total number of NTP packets passed from the NTP application layer to the transportlayer.

::= ntp 2

ntpInErrors OBJECT-TYPESYNTAX CounterACCESS read-onlySTATUS mandatory

7.6.4 Total number of NTP packets reject for any reason by NTP application layer.::= ntp 3

ntpAuthFail OBJECT-TYPESYNTAX CounterACCESS read-onlySTATUS mandatory

7.6.5 Total number of authentication failures. This is a subset of ntpInErrors.::= ntp 4

ntpDesiredAcc OBJECT-TYPESYNTAX INTEGER (0..+2147483647) ACCESS read-onlySTATUS mandatory

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7.6.6 The desired (worst case time) accuracy in microseconds that the time server will attemptto steer to. This variable is related to ntpEstError. Should ntpEstError be greater thanntpDesiredAcc, the NTP alarm condition will be set (ntpSysLeap will be equal to 3). Note: Outgoing NTP packets will have their leap indicator field set to ntpSysLeap.

::= ntp 5

ntpEstErr OBJECT-TYPESYNTAX INTEGER (0..+2147483647) ACCESS read-onlySTATUS mandatory

7.6.7 The current estimated (time) error in microseconds of the time server. This variable isrelated to ntpEstError. Usually, this value is small and constant for a given type of timeserver. However, when primary synchronization is lost, this value will slowly increasewith time as the time server's oscillator flywheels away from true time. ShouldntpEstError be greater than ntpDesiredAcc, the NTP alarm condition will be set(ntpSysLeap will be equal to 3). Note: A primary time server's outgoing NTP packets willhave its leap indicator field set to ntpSysLeap.

::= ntp 6

ntpSysLeap OBJECT-TYPESYNTAX INTEGER

No warning (0),Last minute has 61 seconds (1),Last minute has 59 seconds (2),Alarm condition (clock not synchronized) (3)

ACCESS read-onlySTATUS mandatory

7.6.8 This is a status code indicating normal operation, a leap second to be inserted in the lastminute of the current day, a leap second to be deleted in the last second of the day or analarm condition indicating the loss of timing synchronization. Note: A primary timeserver's outgoing NTP packet will have its leap indicator field set to ntpSysLeap.

::= ntp 7

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ntpSysHostModeSYNTAX INTEGER

reserved (0),symmetric active (1),symmetric passive (2),client (3),server (4),broadcast (5),reserved (6),reserved (7)

ACCESS read-writeSTATUS mandatory

7.6.9 The value of this variable indicates the mode that the host is operating in. Note: This isthe value of the time server's outgoing NTP packet mode field.

::= ntp 8

ntpSysStratum OBJECT-TYPESYNTAX INTEGER

unspecified (0),primary reference (1),secondary reference (2..255)

ACCESS read-onlySTATUS mandatory

7.6.10 This is an integer that ranges from 1 to 255 indicating the stratum level of the local clock.Note: A primary time server sets outgoing NTP packets stratum field and ntpSysStratumto 1.

::= ntp 9

ntpSysPoll OBJECT-TYPESYNTAX INTEGER (6..10) ACCESS read-writeSTATUS mandatory

7.6.11 When the time server is in NTP broadcast mode, this is an integer indicating themaximum interval between successive NTP messages, in seconds to the nearest powerof two. For example a value of 6 means 2^6 or 64 seconds. Note: A primary timeserver's outgoing NTP packet will have its poll field set to ntpSysPoll. Note: This field isequal to 0 when not in NTP broadcast mode. Note, unless this is a time server initiatedNTP packet the value of the poll equals the value set in the in coming packet.

::= ntp 10

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ntpSysPrecision OBJECT-TYPESYNTAX INTEGER (-127..+127) ACCESS read-onlySTATUS mandatory

7.6.12 This is an integer indicating the ultimate precision of the synchronizing clock, in secondsto the nearest power of two. Note: a primary time server's outgoing NTP packet will haveits precision field set to ntpSysPrecision.

::= ntp 11

ntpSysRootDelay OBJECT-TYPESYNTAX COUNTER (0..4294967295) ACCESS read-onlySTATUS mandatory

7.6.13 This is a raw 32 bit number representing a signed fixed point 32 bit number indicating thetotal round-trip delay to the primary synchronization clock source in seconds with thefraction point between bits 15 and 16. Note that this variable can take on both positiveand negative values, depending on clock precision and skew. Note: A primary timeserver's outgoing NTP packet will have its root delay field set to ntpSysRootDelay.

::= ntp 12

ntpSysRootDisp OBJECT-TYPESYNTAX COUNTER (0..4294967295) ACCESS read-onlySTATUS mandatory

7.6.14 This is a raw 32 bit number representing a signed 32 bit fixed-point number indicating themaximum error relative to the primary reference source, in seconds with fraction pointbetween bits 15 and 16. Only positive values greater than zero are possible. Note: Aprimary time server's outgoing NTP packet will have its root dispersion field set tontpSysRootDisp.

::= ntp 13

ntpSysRefClockIdent OBJECT-TYPESYNTAX DisplayString (SIZE (0..4))ACCESS read-onlySTATUS mandatory

7.6.15 This is a four byte ASCII string identifying the particular reference clock. In the case ofstratum 0 (unspecified) or stratum 1 (primary reference), this is a four-octet, left-justified,zero-padded ASCII string. While not enumerated as part of the NTP specification, thefollowing are suggested ASCII identifiers:

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Stratum Code Meaning0 DCN DCN routing protocol0 NIST NIST public modem0 TSP TSP time protocol0 DTS Digital Time Service1 ATOM Atomic clock (calibrated)1 VLF VLF radio (OMEGA, etc.)1 callsign Generic radio1 LORC LORAN-C radionavigation1 GOES GOES UHF environment satellite1 GPS GPS UHF satellite positioning1 ACTS ACTS telephone modem dial-up1 IRIG Inter-Range Instrumentation Group signal

7.6.16 Note, for TrueTime time servers only GPS, ACTS and IRIG are presently used. Further,a primary time server's outgoing NTP packet will have its reference identifier field set tontpSysRefClockIdent.

::= ntp 14

7.7 THE NTSCONTROL GROUP (PRELIMINARY)7.7.1 This group allows for complete control of TrueTime's products. This group emulates the

serial function string commands described in TrueTime's operations manual. Toconfigure the timeserver using the enterprise MIB, use the same syntax as the serialterminal FXX string. Where XX is the function number of the command. As an example,to find the trusted IP hosts for SNMP community one, you would type the following fromthe management station's command line:

#snmp -c system -h 199.37.0.21 set enterprise.1896.3.1.0 "F36C1IP"<Return key>#snmp -c system -h 199.37.0.21 get enterprise.1896.3.2.0<Return key>Response: "F36 C1 Trusted IPs: 199.37.0.26 199.37.0.24 0.0.0.0 0.0.0.0"

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7.7.2 The -c command line switch specifies the community name and the -h switch specifiesthe IP address of the SNMP host agent. Note: the invocation of SNMP will vary from oneoperating system to the next, but this will give you the idea. Please note: the EnterpriseOID addresses; these represent the input and output string buffers in TrueTime'sEnterprise MIB and are formally defined below. The first SNMP set command places thefunction string into the timeserver's command buffer and the following SNMP getcommand reads the result of the set command. It is important to note that any TrueTimefunction string parameter can be issued using this method. Also note: that only onefunction string set may be issued at a time. Do not issue another until the responsestring is set to something other than an null string. Remember it takes time to processthese commands and operating the commands in this fashion ensures that they performwithout undesirable effects. Thus, the entire timeserver setup can be done with SNMP. If these commands are issued from a script or batch file, the setup procedure for anentire timeserver is repeatable and automatic. Another advantage of this facility is thatthe TrueTime Service Department can now help to check the configuration of atimeserver if it is connected to the Internet. As a security precaution, the timeserver canturn on/off the remote configuration feature only through the keypad.

ntpControlInput OBJECT-TYPESYNTAX DisplayString (SIZE (0..255))ACCESS read-writeSTATUS mandatory

7.7.3 This variable emulates TrueTime's serial function command strings. The samecommands issued to the serial port can be sent to this string. Use this variable forSNMP sets of functions strings. Note, setting this variable clears ntpControlOutput to thenull string. See ntpControlOutput below.

::= trapMsg 1

ntpControlOutput OBJECT-TYPESYNTAX DisplayString (SIZE (0..255))ACCESS read-onlySTATUS mandatory

7.7.4 This variable emulates TrueTime's serial function command strings. The samecommands issued to the serial port can be sent to this string. This variable holds theoutput result string from the last setting of the above ntpControlInput variable. Use thisvariable for SNMP gets of function strings. See ntpControlInput above.

::= trapMsg 2

7.8 GPS GROUP VARIABLES7.8.1 The GPS group is present in all TrueTime network products. However, only products

synchronized by GPS will have meaningful data in this group. This group reports on thenumber of satellites that are currently tracked, the current GPS tracking mode, thestrongest signal strength of the tracked satellites in Trimble units, elevation of the GPSantenna in centimeters and the longitude and latitude of the GPS antenna in normalizedbinary units that can be easily converted to radians or degrees. GPS is a satellite base

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time synchronization source and it is the most accurate source of timing for TrueTime'sNTS product line.

gpsGroupValid OBJECT-TYPESYNTAX INTEGER (0..1) ACCESS read-onlySTATUS mandatory for GPS capable units

7.8.2 A test flag indicating if data contained in this SNMP GPS group is valid or not. This flagequals 1 when GPS is used as the time synchronization source and 0 for all othersources.

::= gps 1

gpsNumTrackSats OBJECT-TYPESYNTAX INTEGER (0..8) ACCESS read-onlySTATUS mandatory for GPS capable units

7.8.3 The number of GPS satellites tracked.::= gps 2

gpsNumCurrentSats OBJECT-TYPESYNTAX INTEGER (0..8) ACCESS read-onlySTATUS mandatory for GPS capable units

7.8.4 Current number of GPS satellites used in position and time fix calculations. The numberof satellites available depends on how long the time server has been up, the time of dayand the total amount of clear sky as seen from the GPS antenna. Because of the highfrequency of GPS radio signals, GPS antennas must have unobstructed line of sightfrom the antenna to the satellite to receive data.

::= gps 3

gpsSatTrackMode OBJECT-TYPESYNTAX INTEGER

(0), Automatic Mode(1), Time Mode(2), Survey Static Mode(3), Survey Dynamic Mode

ACCESS read-onlySTATUS mandatory for GPS capable units

7.8.5 Mode of operation for satellite tracking. See section 3.20 of the users manual for acomplete description of these modes. Generally, modes 0 and 1 are used for timeapplications. Mode 2 is useful for more accurate position information when the unit is

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stationary, or slowly moving and mode 3 is for accurate position information when theunit is moving quickly.

::= gps 4

gpsSatMaxSigStrength OBJECT-TYPESYNTAX INTEGER ( 0..30) ACCESS read-onlySTATUS mandatory for GPS capable units

7.8.6 Strongest signal strength of all tracking satellites in Trimble linear units. Generally, thisnumber should be 4 or greater for good reception.

::= gps 5

gpsAltitudeSYNTAX INTEGER (-2147483647..+2147483647) ACCESS read-onlySTATUS mandatory for GPS capable units

7.8.7 Altitude of the GPS antenna in centimeters above, or below the WGS-84 referenceellipsoid. The reference ellipsoid is a rotated ellipse that is centered on the Earth'scenter of mass. The surface of the ellipsoid is not necessarily the same as sea level. The ellipsoid surface may be as much as 100 meters different from actual sea level.

::= gps 6

gpsLongitudeSYNTAX INTEGER (-2147483647..+2147483647) ACCESS read-onlySTATUS mandatory for GPS capable units

7.8.8 Longitude location of GPS antenna where: +2147483647 is maximum east longitude, -2147483647 is maximum west longitude and 0 is Greenwich England. To calculate thelongitude in radians use the following formula (gpsLongitude * PI) / ((2^31)-1) = longitudein radians. For degrees: (gpsLongitude * 180) / ((2^31)-1) = longitude in degrees. Note:longitude varies from -PI to +PI in radians and -180 to +180 in degrees.

::= gps 7

gpsLatitudeSYNTAX INTEGER (-2147483647..+2147483647) ACCESS read-onlySTATUS mandatory for GPS capable units

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7.8.9 Latitude location of GPS antenna where: +2147483647 is the North Pole, -2147483647is the South Pole and 0 is the equator. To calculate the latitude in radians use thefollowing formula (gpsLatitude * PI) / (2*((2^31)-1)) = longitude in radians. For degrees:(gpsLatitude * 90) / ((2^31)-1) = latitude in degrees. Note: latitude varies from -PI/2 to+PI/2 in radians and -90 to +90 in degrees.

::= gps 8

7.9 ACTS GROUP VARIABLES7.9.1 The ACTS group is present in all TrueTime network products. However, only products

synchronized by ACTS will have meaningful data in this group. This group reports on thenumber and status of ACTS dial up modem calls. ACTS is a telephone modem dial-uptime service that is not as accurate as GPS, but does not suffer from the antennarestrictions of GPS.

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actsGroupValid OBJECT-TYPESYNTAX INTEGER (0..1) ACCESS read-onlySTATUS mandatory for ACTS capable units

7.9.2 A test flag indicating if data contained in this SNMP ACTS group is valid or not. This flagequals 1 when ACTS is used as the time synchronization source and 0 for all othersources.

::= acts 1

actsBaudRate OBJECT-TYPESYNTAX INTEGER (300), (1200) ACCESS read-onlySTATUS mandatory for ACTS capable units

7.9.3 Indicates the baud rate setting for the ACTS modem. The ACTS dial-up service accepts300 or 1200 baud. Note: this is a rare case where faster is not better and 300 baudyields the best time accuracy.

::= acts 2

actsFailRedial OBJECT-TYPESYNTAX INTEGER (0..+9999) ACCESS read-onlySTATUS mandatory for ACTS capable units

7.9.4 When the dial-up session fails to connect this is the time in seconds to wait to try again.::= acts 3

actsMaxCallPeriod OBJECT-TYPESYNTAX INTEGER (0..+999) ACCESS read-onlySTATUS mandatory for ACTS capable units

7.9.5 This is the maximum time in hours the ACTS unit will wait between successful calls to theACTS service.

::= acts 4

actsPhoneNum OBJECT-TYPESYNTAX DisplayString (SIZE (0..25))ACCESS read-onlySTATUS mandatory

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7.9.6 This is the phone number of the ACTS dial-up service, including any prefixes needed toreach an outside line or international dialing. Prefixes are separated by a comma fromthe main phone number.

::= acts 5

actsNumberOfCalls OBJECT-TYPESYNTAX COUNTER (0..4294967295) ACCESS read-onlySTATUS mandatory for ACTS capable units

7.9.7 Number of times the time server has called the ACTS dial-up service - weather the callwas successful or not.

::= acts 6

actsGoodCalls OBJECT-TYPESYNTAX COUNTER (0..4294967295) ACCESS read-onlySTATUS mandatory for ACTS capable units

7.9.8 Number of times the time server called the ACTS dial-up service and successfullyreceived the time.

::= acts 7

actsBadCalls OBJECT-TYPESYNTAX COUNTER (0..4294967295) ACCESS read-onlySTATUS mandatory for ACTS capable units

7.9.9 Number of times the time server called the ACTS dial-up service and something was notright. This variable is the sum total of all other ACTS failure types.

::= acts 8

actsFailedInit OBJECT-TYPESYNTAX COUNTER (0..4294967295) ACCESS read-onlySTATUS mandatory for ACTS capable units

7.9.10 Time server's internal modem failed to initialize. If this is excessive, it may indicate atime server hardware failure.

::= acts 9

actsNoDialTone OBJECT-TYPESYNTAX COUNTER (0..4294967295) ACCESS read-onlySTATUS mandatory for ACTS capable units

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7.9.11 Time server's internal modem found no dial tone. This may be caused by a brokenphone line to the time server.

::= acts 10

actsNoCarrier OBJECT-TYPESYNTAX COUNTER (0..4294967295) ACCESS read-onlySTATUS mandatory for ACTS capable units

7.9.12 Time server's internal modem found no carrier. No modem was found at the other endand maybe the phone number for ACTS is wrong.

::= acts 11

actsBusyLine OBJECT-TYPESYNTAX COUNTER (0..4294967295) ACCESS read-onlySTATUS mandatory for ACTS capable units

7.9.13 Time server's internal modem found ACTS line busy. ::= acts 12

actsNoAnswer OBJECT-TYPESYNTAX COUNTER (0..4294967295) ACCESS read-onlySTATUS mandatory for ACTS capable units

7.9.14 The remote ACTS mode did not answer the call. ::= acts 13

actsBadReply OBJECT-TYPESYNTAX COUNTER (0..4294967295) ACCESS read-onlySTATUS mandatory for ACTS capable units

7.9.15 The syntax of the reply from remote modem was incorrect, possibly due to line noise.::= acts 14

actsNoOnTimeMark OBJECT-TYPESYNTAX COUNTER (0..4294967295) ACCESS read-onlySTATUS mandatory for ACTS capable units

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7.9.16 The reply from remote modem had no on time mark, possibly due to line noise.::= acts 15

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NNTTSS--220011..MMAANN AA--11 RReevv AA

APPENDIX ANTP v 3.0 DATA FORMAT per RFC1305

A-1 NTP DATA PACKETA-1.1 The layout of the NTP data packet information following the UDP header is shown below.

LeapIndicator

VersionNumber Mode Stratum Poll Precision

Synchronizing Distance (Root Delay Version 3)Synchronizing Dispersion (Root Dispersion Version 3)Reference Clock IdentifierReference TimestampOriginate TimestampReceive TimestampTransmit TimestampAuthenticator

Leap IndicatorA-1.2 The leap indicator is a 2 bit code which signals an impending leap second to be added or

subtracted in the last minute of the current day. Leap year codes and theircorresponding meanings are shown in the table below.

Bit 0 Bit 1 Meaning0 0 Normal Operation0 1 61 second last minute1 0 59 second last minute1 1 Clock not synchronized

A-1.3 The unsynchronized state is indicated by the NTS-100 whenever the estimatedsynchronization error is greater than the root dispersion. Such conditions typically occurfollowing turn-on, until synchronization with the external source has been achieved, andwhenever the external synchronization input has been removed and the extrapolatedtime error has exceeded the value of the root dispersion.

Version NumberA-1.4 The version number is a three bit integer which specifies the NTP version. The NTS-100

will copy this field from the client requesting packet and return it in this field if it is equalto either 2 or 3. NTP version 1.0 packets are not supported.

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ModeA-1.5 The mode is a three bit integer that determines the functions the NTS-100 module will

perform. TrueTime’s NTS-100 module operates in mode four or server mode. Modefour operation allows the module to synchronize hosts but will not allow the module to besynchronized by another host.

StratumA-1.6 The stratum is an eight bit integer providing the stratum level of the local time source.

TrueTime’s NTS-100 module operates in stratum 1, denoting a primary reference.

Poll IntervalA-1.7 The poll interval is a signed eight bit integer used as the exponent of two to yield in

seconds the minimum interval between consecutive messages. For example, a pollinterval value of six implies a minimum interval of 64 seconds. The NTS-100 does notalter the setting of this field.

PrecisionA-1.8 The precision is a signed eight bit integer used as the exponent of two to yield in

seconds the precision of the local time source and any other hardware affecting the baselevel “jitter” of the time server. This field is set to approximate the time stampingresolution of the NTS-100 which is 10 µs. So the precision byte is set to -16 which isequivalent to a precision of 15.26 µs.

Synchronizing Distance (Root Delay Version 3)A-1.9 The root delay is a signed 32 bit fixed point number representing the predicted roundtrip

delay in seconds to the primary synchronizing source. The fraction point is between bits15 and 16. This value is set to 0 seconds in TrueTime’s NTS-100 module.

Synchronizing Dispersion (Root Dispersion Version 3)A-1.10 The root dispersion is a signed 32 bit fixed point number representing the maximum error

in seconds relative to the primary synchronizing source. This value is a function of theprecision and the quality of the synchronization input option. The user must provide anaccuracy input via Serial I/O Function 36 when the synchronization input option is IRIG-B,ACTS or External 1PPS, since the root primary synchronizing source is not known by theNTS-100 in those cases. When the synchronization input option is GPS, then the NTS-100 will self determine the accuracy. Once the accuracy has been determined, then theNTS-100 sets the root dispersion equal to ten times the square root of the sum of thesquares of the precision and the accuracy, except for the ACTS synchronization option,where the root dispersion is set equal to the accuracy.

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Reference Clock IdentifierA-1.11 The reference clock identifier is a 32 bit code identifying the particular type of timing

source. Strata 0 and 1 use a four-octet, left justified, zero-padded ASCII string. TrueTime’s NTS-100 module operates as Stratum 1 and uses this four-octet string basedon the local time source input as shown in the table below. This setting is determinedbased on the NTS-100 synchronization input option.

Local SourceInput

Reference IdentifierString

GPS “GPS”IRIG B “IRIG”1 PPS “1PPS”ACTS “ACTS”

Reference TimestampA-1.12 The reference timestamp is a 64 bit timestamp format representing the local time at the

last update. TrueTime’s NTS-100 module’s reference timestamp is the last time that avalid synchronization source signal was present.

Originate TimestampA-1.13 The originate timestamp is a 64 bit timestamp format representing the time that the

request left the client host.

Receive TimestampA-1.14 The receive timestamp is a 64 bit timestamp format representing the time that the

request arrived at the service host.

Transmit TimestampA-1.15 The transmit timestamp is a 64 bit timestamp format representing the time that the reply

left the service host.

AuthenticatorA-1.16 This is a 96 bit field containing the authenticator information as described in Appendix C

of RFC-1305. This field is not implemented by the NTS-100.

A-2 SNTP V 3.0 DATA FORMAT PER RFC1361A-2.1 When the NTS-100 replies to requests from SNTP clients, the packet format is the same

as the NTP packet format described above, with these differences:

Leap IndicatorA-2.2S The NTS-100 will set these 2 bits to either 0 (normal) or 3 (unsynchronized) only.

Version NumberA-2.4S The NTS-100 will copy this field from the client request packet and return it in this field.

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Reference TimestampA-2.12S This field is set to the time that the reply left the NTS-100 server host.

Receive TimestampA-13S This filed is set to the time that the reply left the NTS-100 server host.

Transmit TimestampA-15S This field is set to the time that the reply left the NTS-100 server host.

AuthenticatorA-16S This field is not used in SNTP.

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NNTTSS--220011..MMAANN BB--11 RReevv AA

APPENDIX BTIME PROTOCOL per RFC868

B-1 INTRODUCTIONB-1.1 This protocol provides a site-independent, machine readable date and time. The TIME

service sends back to the originating source the UTC time in seconds since midnight onJanuary 1, 1900.

B-1.2 This protocol may be used either above the Transmission Control Protocol (TCP) orabove the User Datagram Protocol (UDP). The NTS-100 implements the TIME protocolonly above the UDP.

B-1.3 When used via UDP the TIME service works as follows:

Server: Listen on port 37 (45 octal).Client: Send an empty datagram to port 37.Server: Send a datagram containing the UTC time as a 32 bit

binary number.Client: Receive the TIME datagram.

B-1.4 The server listens for a datagram on port 37. When a datagram arrives, the serverreturns a datagram containing the 32-bit time value. If the server is unable to determinethe time at its site, it should discard the arriving datagram and make no reply.

B-2 THE TIME FORMATB-2.1 The time is the number of seconds since 00:00 (midnight) 1 January 1900 UTC, such

that the time 1 is 12:00:01 AM on January 1, 1900 UTC; this base will serve until the year2036.

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APPENDIX CIRIG B TIME CODE

C-1 INTRODUCTIONC-1.1 The document 200-70 "IRIG STANDARD TIME FORMATS" by the Telecommunications

Working Group, Inter-range Instrumentation Group, Range Commanders Councildescribes IRIG B, IRIG H and IRIG E time codes. It is available by writing Secretariat,Range Commanders Council, White Sands Missile Range, New Mexico, 88002.

C-1.2 The standard time formats of IRIG codes were designed for use in missile, satellite andspace research programs. Use of these codes facilitates efficient interchange of testdata. These formats are suitable for recording on magnetic tape, oscillographs, film andfor real-time transmission in both automatic and manual data reduction. IRIG B from theModel NTS-100 is suitable for remote display driving, magnetic tape recording and manyother uses. IRIG codes, in the strict sense, encode Universal Coordinated Time (UTC) in24 hour format and not local time. Nonetheless, this instrument can encode UTC or localtime in either 24 or 12 hour formats.

C-2 IRIG B CODE FORMATC-2.1 Reference figure C-1. The level shifted, pulse-width modulated, serial format of IRIG B

is divided into three segments. The first segment encodes time-of-year in binary-coded-decimal (BCD) notation. The second segment encodes control functions. This segmentis generally available for data of the user's choice. In the IRIG-B code output of ModelNTS-100, this segment may encode worst-case time error flags as explained below. Thethird segment sometimes encodes time-of-day in straight binary seconds (SBS) notation.This segment is not encoded by the Model NTS-100.

C-2.2 These three segments are contained within one "frame". The frame length for IRIG B is 1second long and contains 100 "elements" (pulses) each of which start every 10milliseconds.

C-2.3 An element may represent either a binary zero, a binary one, a reference marker or aposition identifier. A zero is 0.2 of the duration of an element, a one is 0.5 of the durationof an element and a position identifier or reference marker is 0.8 of the duration of anelement. A reference marker locates the beginning of each frame and a positionidentifier marks the end of every ten elements. IRIG B has ten position identifiers perframe.

C-2.4 The elements prior to position identifier P5 comprise the time-of-year segment. The firstten elements encode the seconds, the second ten elements encode the minutes and soon through days. Each element is a digit in a binary number with a place value sequence1-2-4-8.

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C-3 EMBEDDED WORST-CASE TIME ERROR FLAGSC-3.1 Five flags are encoded in the control function segment of the IRIG B code. The first flag

encoded at element P5+40ms is the LOCK indicator. It is a binary 1 when the unit haslost contact with satellite signals. The second flag encoded at element P5+60ms is abinary 1 when the worst-case time error exceeds threshold 1 as described in SECTIONIII, "SERIAL I/O FUNCTION 05 -TIME QUALITY ENABLE/SETUP". Element P5+70msis a binary 1 when the worst-case time error exceeds threshold 2. Element P5+80msencodes a binary 1 when the error exceeds threshold 3 and P5+90ms when the errorexceeds threshold 4.

Figure C-1 (IRIG-B)

10 20 30 40 50 60 70 80 90 00

P5 PR

RE

IRIG-B TIME CODE FORMAT

TIME FRAME 1 SECONDTIME

Time in 0.01 s

TYPICAL MODULATED CARRIER (1000Hz)

HOUR

BCD Time-of-Year

P0 PR P P2

0.01 s Index Marker,Duration 2 ms

0.1 s Position IdentifierDuration 8 ms

REF SECOND

On-Time

MINUTE

P3 P4

DAY

Control Functions

P6 P7

Lock Indicator

P8 P9 P0

1 2 4 8 10 20 40 1 2 4 8 10 20 40 1 2 4 8 10 20 40 10 20 40 801 2 4 8

Binary One5 ms Typical

Time Quality 4

Time Quality 1Time Quality 2Time Quality 3 10 ms Typical

100 200

3XX

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APPENDIX D

DETAILED DRAWINGS / BILL OF MATERIALS

network time server irig nts-100 600-201 · nts-201.man iii rev. a section vii 6-1 simple network...

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