1 shielded cable performance parameters network cable solutions module 2-j

SHIELDED CABLE SHIELDED CABLE PERFORMANCEPERFORMANCEPARAMETERSPARAMETERS

NETWORK CABLE NETWORK CABLE SOLUTIONSSOLUTIONSMODULE 2-JMODULE 2-J

SCREEN TECHNOLOGYSCREEN TECHNOLOGY

Screening of UTP cables Shielded Screened or Foiled

Known as ScTP in the Americas. Low usage

Known as FTP in Europe 80% of installed LAN’s

Primarily in UK, France, Germany

SCREEN TECHNOLOGYSCREEN TECHNOLOGY

Advantages Greater immunity from RFI/EMI interference.

Yields lower bit error rate. Greater immunity from radiated signals.

Yields a more secure cabling solution.

Disadvantages Higher installed cost

Material and Labor Greater difficulty in installation Shorter link lengths under certain conditions

SCREENED TECHNOLOGYSCREENED TECHNOLOGY

Two basic construction FTP (ScTP)

Four pair cable with an overall foil shield. Drain Wire

S-FTP Four pair cable with individually pairs. Overall braided shield. Drain Wire

Similar to the STP cables used in Token Ring applications.

SCREENED TECHNOLOGYSCREENED TECHNOLOGY

100 ohm Shielded cabling Design Not 100 Ohm UTP with a shield. Shielded 100 Ohm twisted pair is designed to

provide certain system performance characteristics It can have a large number of variations.

STANDARDSSTANDARDS

TIA/EIA 568-A Has references to 4 pair, 100 ohm shielded cable It is allowed if it meets the same performance

specifications as UTP. No description of cable construction. No specifications on the connector shield interface. No specifications on shielding performance. No guideline on how to design or install a system in

order to maintain shielding performance

STANDARDSSTANDARDS

TIA Task Group Formed to fill the gaps and define specific.

Component Requirements. Installation Requirements.

Task Group Definition 4 pair to be used as a standard. Overall foil shield and drain wire to be the basic

construction. Other shields and braids may be added as long as basic

construction is maintained.

STANDARDSSTANDARDS

TIA Task Group Task Group Definitions

Performance categories are the same as for UTP. Color coding is the same. 8 position jack is maintained. Jack to plug shield has been standardized and a test

has been developed to verify shielding performance of a mated pair.

Requirements for shield continuity and grounding have been determined.

STANDARDSSTANDARDS

ISO/IEC 11801 More complete than TIA EIA 568A, but has gaps.

List tentative specifications on cable and connector shielding performance.

Provides basic installation guidelines on shield continuity and grounding.

Allows both 2 pair and 4 pair. Allows 120 ohm impedance.

STANDARDSSTANDARDS

ISO/IEC 11801 Allows both:

Overall shield construction Individually Shielded Construction

EN 55022 This directive defines the limits and methods of

measurement of ratio frequency interference characteristics of information technology equipment.

Limits on what a LAN can emit. Similar to limit imposed by the FCC in the U.S.

STANDARDSSTANDARDS

EMC & Cabling Systems Unshielded or badly shielded cable cannot pass the

European emissions directive at much more than 30 Mhz without encoding schemes or filter devices.

The FCC in the United States limits the transmission frequency at 30 Mhz

Through encoding schemes transmission at 31.25 Mhz is possible because it spreads the energy over a wider frequency.

SHIELDING EFFECTSHIELDING EFFECT

Emissions Screens reduce the radiated signals by a minimum

of 20 dB.

STANDARDSSTANDARDS

EN 55024 Defines the degree of sensitivity of a system with

regard to the following: Electrostatic Discharge Immunity, Part 2 Radiated Immunity, Part 3 Fast Transient Immunity, Part 4 Induced Interference, Part 6

POSITIONPOSITION

Strong position in Europe. In areas where shielded cabling is used.

Reflects concerns over more stringent regulatory controls on electromagnetic emissions.

Concerns regarding interference from electromagnetic noise.

European Community used the term electromagnetic compatibility (EMC) to encompass both concerns.

EMC CONTROLEMC CONTROL

Shielding is not the only means of EMC control. Well balanced Non shielded twisted pair cables are

effective in limiting emissions and interference at current digital transmission frequencies.

Electronic techniques are used to limit transmission frequencies and maintain acceptable bit error rates in typical office environments.

EMC CONTROLEMC CONTROL

UTP Cable EMC control dependent on system balance.

Balance dependent on pair twist rate. Pair twist rate is close to manufacturing minimum.

Crosstalk performance dependent on variation of twist length.

Ability to further improve crosstalk by twist is limited.

APPLICATIONAPPLICATION

Emission Emission standards, when tested, are for “typical”

installations which is done in a controlled laboratory environment field installations may be different..

Cannot cover all installations variables.

Immunity Influenced by nearby machinery and equipment

sources. Influenced by nearby sources of RFI.

ADVANTAGES OF SHIELDINGADVANTAGES OF SHIELDING

Advantages Take over at point that pair twists leave off and

provide electromagnetic interference control at higher frequencies.

Individually shielded cables can provided additional immunity to crosstalk that is not achievable by pair twisting.

APPLICATIONAPPLICATION

Shielded cables are used to augment EMC characteristics of UTP type cables. Provide additional control for critical networks. Additional immunity over eletromechanically noisy

environments. Can be viewed as an additional insurance policy.

LINK LENGTHLINK LENGTH

Due to the shield a thicker primary insulation is required. To meet the same attenuation and impedance

specifications as that of UTP. It is impractical to make a 24 AWG patch cord so

that it will fit modular jacks. In Europe a 26 AWG cord is allowed.

Attenuation in a 26 AWG cord can be as much as 1.5 times higher than a 24 AWG solid cable.

24 AWG stranded is 1.2 times.

CONNECTORSCONNECTORS

The trend in the United States and most other areas is to standardize on the eight position jack. Standardized interface to most LAN equipment.

Other connectors available that can utilize that of 24 AWG cable. Non standard designs.

GROUNDINGGROUNDING

Two methods of grounding are currently in use. Star where one end of the cable is grounded. Mesh where both ends of the cable are grounded.

The mesh type system may cause ground loops if both grounding points are not at the same ground potential.

The star grounding configuration is recommended.

GROUND LOOPSGROUND LOOPS

Ground Loops if Mesh Grounding is used. To assure that ground loops do not occur, measure

the following between the shield and the green grounding conductor of the outlets servicing the work area.

Resistance should be less than 3.5 ohms. Voltage should be less than 1 VRMS

PERFORMANCE TESTINGPERFORMANCE TESTING

Performance Testing Standards Recently the ISO/IEC 11801 standardized the

performance testing of shielded components in terms of Transfer Impedance.

The TIA TSB will also standardize on this method. Prior to this manufacturers decided on the method to

be used.

SUMMARYSUMMARY

The benefits of a shielded cable system is that it will minimize the variability of installed twisted pair cabling balance and add signal to noise margin.

SHIELDED CABLE SHIELDED CABLE PERFORMANCE PARAMETERSPERFORMANCE PARAMETERS

QUESTIONS?QUESTIONS?

FTP CABLE INSTALLATIONFTP CABLE INSTALLATION

NETWORK CABLE NETWORK CABLE SOLUTIONSSOLUTIONSMODULE 2-KMODULE 2-K

FTP INSTALLATIONFTP INSTALLATION

Scope To provide the installer with the guidelines to

properly handle high grade FTP cable during installation.

Proper handling assures optimum cable performance for intended present and future applications.

Construction Pairs are twisted more

tightly and built to specific design constraints in a Cat. 5 cable.

A precise twist is induced into the bundled 4-Pairs prior to jacketing.

Geometry becomes critical to maintain performance.

Damaging or changing the position of the pairs adversely affects the ability of the cable to carry high data rates.

Minimum Bend Radius Cables exceeding the minimum bend radius will

exhibit degraded performance. Returning flawed section to a larger diameter will

not correct the fault. the cable will still exhibit the degraded

transmission performance

Minimum Bend Radius Review conduit bends Exercise care in installing cable in trays Do not bend cable over corners Do not coil cable tightly and stuff into work box.

Store excess coiled in ceiling Exercise care when dressing cables

Minimum Bend Radius Sweep cables to avoid bends and kinks.

Kinking the cable changes the shape of the core, moves the pairs and changes the geometry

Damage is permanent

Service Loops 1-3 feet loops at termination points Leave service loops along the route of the cable

FTP INSTALLATION FTP INSTALLATION

Maximum Tensile Loading Exceeding the maximum tensile loading will

adversely affect the performance of the cable. Quality of the cable is a affected long before damage is

visible Physical stress must be guarded against during

installation and in suspended cable runs. Cables should be well supported. Correcting cable tension will not reverse the effect

of over-loading. Maximum cable loading for an FTP four pair cable is

25 lb.

Over-Cinching Over-cinching causes compression and distortion of

the cable, degrading cable performance. Cable ties must never distort the jacket. Avoid using staples Never crush the cable with staples.

Avoid using staples because they crush the cable

The wraps should not distort the jacket of the cable

A properly installed tie wrap can easily be moved up and down and twisted around the bundle

Over-Cinching Select non-compression

cable management accessories

Velcro tie wraps “D” rings Nail on cable clamps

Cable Bundles Assure that weight of bundle in not compressing

cable jacket. Exert care when running a large cable bundle

around a bend In trays fiber cable should be placed on the top and

FTP on the bottom.

Cable Lengths Horizontal runs are limited to 90 meters or less. Work area equipment cables are limited to 3 m or

less. Patch cords, jumpers, and cross connects are

limited to 7 m or less in the telecommunications closet.

Other Installation Suggestions Do not share bore holes with power wires. Never install components of unknown or

questionable manufacture or quality. Keep wire away from heat sources, heat ducts and

pipes. Leave one to three foot service loops at outlets and

connection points. When existing a cable tray it is recommended that

a service loop is left. Use proper support methods when installing a cable

in a dropped ceiling.

Cable Installation Each horizontal run should be a continuous link to a

single work area. Bridging of horizontal runs is not acceptable. Do not split pairs between multiple outlets.

All four pairs must be connected to a single jack or connector.

FTP CABLE INSTALLATIONFTP CABLE INSTALLATION

FTP CABLE TERMINATIONFTP CABLE TERMINATION

NETWORK CABLE NETWORK CABLE SOLUTIONSSOLUTIONSMODULE 2-LMODULE 2-L

FTP TERMINATIONFTP TERMINATION

Termination of FTP cable from UTP differs in that: Shield continuity must be maintained throughout

the system. Shield must be grounded.

FTP TERMINATIONFTP TERMINATION

Termination Procedures Strip cable to expose conductors, drain wire and

foil. Cut foil even with outer jacket. Slip cable over grounding tab. Be sure that the tab

is on the inside of the foil shield. Bend drain wire ground tabs against the cable. Wrap the drain wire around the tabs and the cable. Apply tie wrap to assure good contact of drain wire

to grounding tab. Punch pairs down. Snap metal shield over connector.

FTP CABLE TERMINATIONFTP CABLE TERMINATION

LAN CABLING SYSTEMS LAN CABLING SYSTEMS OVERVIEWOVERVIEW

NETWORK CABLE NETWORK CABLE SOLUTIONSSOLUTIONSMODULE 3-AMODULE 3-A

LOCAL AREA NETWORKLOCAL AREA NETWORK

A Local Area Network or LAN is a system that interconnects data devices to share information at high speeds in a limited geographic area. Accomplished with a combination of hardware and software.

LAN CABLINGLAN CABLING

LAN cabling provides a path to distribute data signals

The objective of the cabling systems is to be reliable and error free

Could be the most expensive component of a LAN.

May restrict technology. Important element in high speed LAN’s

NETWORK CABLING FACTNETWORK CABLING FACT

70% of all LAN problems are directly related to the media.

90% of all LAN problems are directly related to the media and physical hardware.

CABLING FACTSCABLING FACTS

Why you should assure only the best cabling system is installed in your facility.

LIFE CYCLESLIFE CYCLES

Software - 1 Year PC and Micros - 5 Years Mainframe - 10 years Cabling System - 16 years Building Shell - 50 years

NETWORK INVESTMENTNETWORK INVESTMENT

Software - 54% Intelligent Workstations - 34% LAN Equipment - 7% Cabling - 5%

DOWNTIMEDOWNTIME

70% of all downtime is cable related. Downtime costs run between $1000 to

$50,000 per hour

SPEED FOR DATASPEED FOR DATA

Past 1.2 kbps. 9.6 kbps. 19.2 kbps. 4 Mbps.

Current 10 Mbps. 16 Mbps. 100 Mbps. 155 Mbps. 1 Gbps.

Near Future 10Gbps, 40Gbps

PAST PRACTICESPAST PRACTICES

Cabling usually was an afterthought Most cabling systems were system specific. Objective was to spend as little as possible. Little was known regarding cable

technology on the part of decision makers.

CABLING DESIGN CABLING DESIGN CONSIDERATIONCONSIDERATION

What is the current network speed. Over what distances will the data be

transmitted. Applicable LAN standards. What are the applicable fire codes. What applications will the cable plant need

to support in the future.

LAN CABLE CHOICESLAN CABLE CHOICES

Coaxial cable (Coax) Shielded twisted pair (STP) Unshielded twisted pair (UTP) Fiber optic cable

COAXIAL CABLESCOAXIAL CABLES

Construction single conductor Thick dielectric Braided shield

High Bandwidth Several types Ethernet LANs

COAX TERMINATIONCOAX TERMINATION

Connector types used on coax Thicknet/N type Thinner or IBM 3270/BNC type Video/F type

SHIELDED TWISTED PAIR CABLESHIELDED TWISTED PAIR CABLE

Two types IBM type cable

150 ohm Each pair individually shielded Overall braided shield

ScTP or Foiled 100 ohm Pairs not individually shielded Overall foil shield

High Bandwidth Token Ring 150 Ohm STP cables based on IBM cable

STP TERMINATIONSTP TERMINATION

connector types used on STP STP Data connector

Self shorting

UNSHIELDED TWISTED PAIR UNSHIELDED TWISTED PAIR CABLECABLE

Construction Two to four individually twisted pairs

EIA/TIA-568 A specifies four pair Cables up to 25 pair available

No shield 24 AWG solid conductor

Stranded conductor for patch cords Small in size Performance defined to 100 MHz

UNSHIELDED TWISTED PAIR UNSHIELDED TWISTED PAIR CABLECABLE

Five categories of UTP cable. Category designation indicates cables performance In today’s LANs only Category 3 and Category 5 are

used and the Category 5 enhanced

UTP TERMINATIONUTP TERMINATION

Connectors used in UTP termination 8 position RJ-45 type modular plug

used to terminate cables 8 position modular jack

Used to terminate cables at wall plate Punch down blocks

Used to terminate cables in closets 66 blocks 110 blocks

UTP TERMINATIONUTP TERMINATION

FIBER OPTIC CABLEFIBER OPTIC CABLE

Two optical fibers need for a LAN circuit Several types of coatings and jacketing

Tight buffer Loose tube gel filled Multipurpose indoor/outdoor

Bandwidth is unlimited.

FIBER OPTIC CABLEFIBER OPTIC CABLE

Developed to meet bandwidth hungry applications

Transmits any type of signal voice, video, data analog or digital

Future unlimited Current limitations due to electronics

FIBER OPTIC TERMINATIONFIBER OPTIC TERMINATION

Fiber optic cable termination on both ends with a connector

Connectors joined by barrel connector Many types of connectors on the market

currently ST type most popular SC is recommended standard in TIA/EIA-568A

FIBER OPTIC TERMINATIONFIBER OPTIC TERMINATION

LAN TOPOLOGIESLAN TOPOLOGIES

Bus Ethernet

Ring Token Ring

Star TIA/EIA-568A

BUS TOPOLOGYBUS TOPOLOGY

Advantages Low cable usage Simplified cable management

Disadvantages Design Complexity Preplanning is a requirement Cable failure will bring down the network

RING TOPOLOGYRING TOPOLOGY

Advantages Low cable usage Simplified cable management

Disadvantages Design Complexity Preplanning is a requirement Difficult servicing the media Multiple potential failure points

STAR TOPOLOGYSTAR TOPOLOGY

Advantages Easy to design Minimal preplanning required Simplified servicing and maintenance Increased Network reliability

Disadvantages Higher cable usage Central point of failure

NETWORK COMPONENTS & NETWORK COMPONENTS & CABLESCABLES

Equipment Room Main Distribution Frame Telecommunications Closet Patch Panel Cross-Connect Block (“66”, “110”) Hub (MAU) Gateway Router, Bridge

LAN CABLING SYSTEMS LAN CABLING SYSTEMS OVERVIEWOVERVIEW

LAN TROUBLESHOOTINGLAN TROUBLESHOOTING

NETWORK CABLE NETWORK CABLE SOLUTIONSSOLUTIONSMODULE 3-BMODULE 3-B

If the LAN cabling is in question or has been determined to be at fault, then the following steps can be followed to determine what the specific problem is.

1. Find the Cable Locate and identify both ends of the cable in

question.

2. Is the cable carrying traffic With your test equipment check the cable for noise.

Readings in the frequency for the systems topology greater than 300 mV probably mean the link is active.

Shut down the link.

3. Noise measurement Once the link is shut down, the noise measurement

should be carried out again to check for signals from outside sources.

4. Connectivity Check pin to pin connectivity of the cable. Look for

Wiring reversals Shorts or opens

5. Length Next test that should be performed using a hand

held tester or TDR for length. Is the length within specification.

6. Impedance Using an TDR or a hand held meter test for

impedance. Ideal TDR plot is a flat line. Reflections > +/-10% should be investigated.

7. Average and Impulse Noise Using wideband AC voltmeter look at frequencies

up to 100MHz for activity. Background level of 70 mV is acceptable. Narrow down the frequency to determine source.

Low frequencies-AC power, lights, motors. Middle frequencies-computer switching power supplies, light

dimmers, medical equipment. High frequencies-radio, television, microwave broadcasts or

network traffic (NEXT).

8. Attenuation Using an injector and a power meter test the cable’s

loss characteristics. Test through all patch panels and cross connects and

patch cords. Be aware that some shielded cables have high

capacitance and high attenuation at high network speeds.

9. Near End Crosstalk Using a hand held tester check for near end crosstalk.

If these tests have negative results the cause of the LAN failure is all probability not the cable plant.

For fiber optic cable the procedure is much simpler. Using an OTDR determine if the length is correct

and if the attenuation is within limits. Bandwidth may become an issue if it is an older cable

plant. Bandwidth cannot be tested in the field with any degree of

accuracy.

LAN DESIGN LAN DESIGN CONSIDERATIONSCONSIDERATIONS

NETWORK CABLE NETWORK CABLE SOLUTIONSSOLUTIONSMODULE 4-AMODULE 4-A

LAN DESIGNLAN DESIGN

Standards should be considered with minimum requirements.

Different customers have different needs. Design a system that fits the customer.

Work Area Requirements Closet Requirements Backbone Distribution Requirements Horizontal Distribution Requirements

Systems Evaluation Types of PC’s Bandwidth hungry applications

CAD Financial traders

Video, Multimedia, Teleconferencing Modems or fax lines at the desk Voice systems

Network to be installed 10Base-T 100Base-TX ATM FDDI

Future migration plan Horizontal Media

UTP Fiber to the desk STP Special cables

Connectors T568A or B ST or SC or FDDI Hardware selection Application specific

Network Equipment Connections Installation options

Backbone Media UTP Fiber STP Future growth requirements

Distribution Horizontal

Star, Bus, Ring Backbone

Star, Bus, Ring Collapsed Backbone

Telecommunications Closets Size Layout Construction

Horizontal Distribution Cellular floor Conduit Drop ceiling Raised floor

Horizontal and Backbone Pathways Lengths Routing EMI sources RFI sources Fire codes

LAN Design Process Determine requirements at the work area.

Outlets Media LAN Equipment

Determine requirements for telecommunication closets.

Space Hardware

Determine Horizontal distribution Pathways

Determine Backbone Distribution Pathways Media LAN Equipment

LAN Systems Two choices

Standards Driven Technology Driven

Standards DrivenStandards Driven Best choice because the LAN will serve the

customer for a much longer period.

WORK AREA DESIGN WORK AREA DESIGN CONSIDERATIONSCONSIDERATIONS

NETWORK CABLE NETWORK CABLE SOLUTIONSSOLUTIONSMODULE 4-BMODULE 4-B

WORK AREAWORK AREA

Standards require a minimum of two cables per area. Not necessarily in the same faceplate. Pair splitting not allowed. One UTP

Other cable can be UTP STP Optical fiber

WORK AREAWORK AREA

Jacks Eight position modular jack RJ-45 type. Same category as the cable.

Can be higher category. Link category is determined by lowest performing

component. Pin assignments per T568A or T568B.

UTP/ScTP TERMINATIONUTP/ScTP TERMINATION

UTP / ScTP TERMINATIONUTP / ScTP TERMINATION

PIN 1 2 3 4 5 6 7 8

T568A Pair 3 3 2 1 1 2 4 4

Color W-G G W-O BL W-BL O W-BR BR

T568B Pair 2 2 3 1 1 3 4 4

Color W-O O W-G BL W-BL G W-BR BR

UTP/ScTP TERMINATIONUTP/ScTP TERMINATION

Selection of termination options. T568A

Corresponds to international ISDN Standard. Preferred pinouts in TIA/EIA 568-A Standard. Backward compatible to USOC for pairs 1 and 2.

T568B Most widely specified worldwide for data installations. Backward compatible to USOC, pair 3 corresponds to

pair 2. Subset of IEEE 802.3 10BASE-T

Note USOC is a nested configuration on that is the most

commonly used for voice systems in the U.S.

WORK AREAWORK AREA

Work Area Hardware Must be of equal or higher category as the

horizontal cable. Must be securely mounted at planned locations. Must be easily accessible. Fiber optic connectors that are approved.

2 simplex SC’s 2 simplex ST’s 568SC

WORK AREAWORK AREA

Application Specific Components Should not be installed as a part of the horizontal

cabling. Must be outside the faceplate.

WORK AREAWORK AREA

Cable Termination All four pairs must be terminated to a single

connector. pair splitting is not allowed.

Bridged taps and splices are not allowed.

EQUIPMENT CORDSEQUIPMENT CORDS

UTP/ScTP Equipment Cords Same Category or higher as the horizontal cable. Preterminated equipment cords for a Category 5

systems should be purchased from a qualified supplier.

Typically the hardware manufacturer.

EQUIPMENT CORDSEQUIPMENT CORDS

Fiber Optic Equipment Cords Same fiber type as the horizontal cabling. Must be a two fiber (duplex) cable. Labeling must indicate crossover function.

WORK AREAWORK AREA

Multi User Assembly and Consolidation Point Must be manageable in size.

Serve 6 to 12 users. Permanently located. Work area cables clearly labeled Outlet to be marked with maximum allowable work

area cable length.

WORK AREAWORK AREA

Locating Outlets Coordinate outlet locations with intended floor

plan. Otherwise 2 outlet boxes per 100 sq ft (10 sq m).

Mount outlets between 15 in and 48 in (380 to 1220 mm) above the finished floor.

Unless local codes differ.

WORK AREAWORK AREA

Unterminated Cables Stored in outlet boxes with a face plate. Face Plate label should identify the outlet box is for

telecommunications use.

Exposed Cable Cable installed between the telco closet and the

work area outlet shall not be installed in the work area or any other space with public access.

WORK AREAWORK AREA

Modular Furniture Raceways closest to the floor should be used for

power cable. Modular furniture with beltways is preferred.

Belts above desk level are designed for telecommunications use.

Under no circumstances should communications cable share a raceway with power cable without separation.

WORK AREA DESIGN WORK AREA DESIGN CONSIDERATIONSCONSIDERATIONS

TELECOMMUNICATIONS TELECOMMUNICATIONS CLOSET DESIGN CLOSET DESIGN

CONSIDERATIONSCONSIDERATIONS

NETWORK CABLE NETWORK CABLE SOLUTIONSSOLUTIONSMODULE 4-CMODULE 4-C

TELECOMMUNICATIONS CLOSETTELECOMMUNICATIONS CLOSET

Telecommunications Closet This is the transition point between the backbone

cable and the horizontal cable. Should be dedicated to the telecommunications

function. Minimum of one per floor.

Additional closets if: The floor area served exceeds 10.000 sq ft (1000 sq m) The horizontal distance exceeds 300 ft (90 m)

TELECOMMUNICATIONS CLOSETTELECOMMUNICATIONS CLOSET

Recommended closet sizing on a worker area having 100 sq ft (10 sq m)

Building less than 5000 sq ft (500 sq m) can be served by a small closet with a minimum size of 2 feet by 8.5 feet (0.6m by 2.6m).

TELECOMMUNICATION CLOSETSTELECOMMUNICATION CLOSETS

Location Locate closets near the geographic center of the

floor space that it is intended to serve Reduces cabling distances Aids in avoiding multiple closets

Minimum of one closet per floor recommended

Closets refer to one of two types of areas Main Distribution Frame (MDF)

Logical center of the Star Topology Central control point for cable plant administration Hosts devices (mainframe, PBX) located nearby

Intermediate Distribution Frame (IDF) Subordinate to the MDF Transition point between Backbone and Horizontal

cable Control point for local cable plant administration

Requirements Minimum of two wall covered with plywood. No false ceilings.

Allows for easier cable routing Access to the main building grounding electrode 36 inch by 80 inch (0.91 m x 2 m) door.

Hinged to open out

Requirements Electrical

Two 15 amp 120 volt isolated ground circuits. (Minimum) Two 15 amp 240 volt isolated ground circuits. (Minimum) Ideal if perimeter outlets are placed every 6 feet (1.8

meters). Lighting

50 footcandles (540 Lx) at 3 feet (90 cm) above the floor.

Separation LAN cable components should not be co-located with

electrical panels or high voltage equipment. Do not share with custodial or storage functions.

Requirements Temperature

64 degrees F to 75 degrees F 18 degrees C to 24 degrees C

Humidity 30 to 55% relative (non-condensing)

Heat Dissipation 750-5000 BTU/hr per cabinet

Cabling Practices Multiple types of media used in backbones should

be cross connected in the same closet. Horizontal cables serving the same work areas

should be terminated in the same Closet. Cables should have appropriate cable management

and cable organization hardware to eliminate stress on the cables.

Terminations Horizontal and Backbone cables must be

terminated on hardware meeting or exceeding the category of the cable.

Routine moves and changes must not be accomplished by retermination of fixed backbone or horizontal cables.

Jumpers or patch cords should be used. Application specific devices should be placed

outside the Horizontal Cross-connect.

Factory Pre-terminated Patch Cords Reduces the performance variations due to field

cabling practices. Should be the same category or higher than the

cable plant installed.

Cross Connect Jumpers, patch cords, cross-connects, connecting

equipment or backbone cable with horizontal cable should not exceed 7 meters.

Equipment Rooms Should house only equipment directly related to the

telecommunications system. Usually equipment that is common to several floors is

housed in an equipment room. Must meet all the same requirements as a

Telecommunications Closet. Minimum size 150 sq ft (14 sq m).

0.75 sq ft (0.07 sq m) per 100 sq ft (10 sq m).

Sources of EMI / RFI Telecommunications closets and equipment rooms

should be located away from sources of EMI and RFI Check for

Electrical power supply transformers. Motors and generators. X-ray equipment Radio and radar transmitters. Photocopy equipment.

It is not only the copper cable media that is susceptible to EMI / RFI but also the LAN equipment.

Grounding and Bonding Must meet all local codes Should meet the requirements of TIA/EIA-607 Grounding points should be easily accessible in all

closets.

Electrical Protection All telecommunications cables that extend outside

of a building is susceptible to extraneous voltages or currents.

Exceptions are all dielectric optic cables. It is recommended that Secondary Protection be

installed on all cables that exit the building to protect electronic equipment.

TELECOMMUNICATIONS TELECOMMUNICATIONS CLOSET DESIGN CLOSET DESIGN

CONSIDERATIONSCONSIDERATIONS

HORIZONTAL DESIGN HORIZONTAL DESIGN CONSIDERATIONSCONSIDERATIONS

NETWORK CABLE NETWORK CABLE SOLUTIONSSOLUTIONSMODULE 4-DMODULE 4-D

HORIZONTALHORIZONTAL

Considerations Cable plant should facilitate ongoing adds, moves,

changes, and maintenance. Should accommodate current use requirements. Should be designed to accommodate future

equipment and service changes.

Standards Recognized Horizontal Media TIA / EIA 568-A

100 ohm Unshielded Twisted Pair (UTP). 150 ohm Shielded Twisted Pair (STP). 62.5/125 um duplex optical fiber cable.

ISO 11801 and TIA/EIA 568-A 100 ohm Screened Twisted Pair (ScTP).

a.k.a. Foil Twisted Pair (FTP)

Composite, Hybrid Cables In horizontal applications it is acceptable to use

composite or hybrid cables as long as each individual cable under the shared sheath exhibits standards compliant performance.

Crosstalk requirements are more stringent than for individual cables.

UTP Advantages

Low cost Simple installation Supports most applications New applications are designed for use with UTP

Disadvantages Susceptible to EMI/RFI Distance limitations

STP/ScTP/FTP Advantages

Good EMI/RFI immunity Disadvantages

Difficult to install Higher installed cost Improper shield and grounding installation can result in

the cable acting as an antenna

Optical Fiber Advantages

Immune to EMI/RFI Unlimited bandwidth Longer distances Supports all applications Ease in testing

Disadvantages Longer installation time Highest installed cost

Topology Standards approved topology is the Star.

Each workstation has its own cable terminated at the horizontal crossconnect in the telecommunications closet.

Selection of Horizontal Media Minimum of two telecommunications outlets must

provided for each individual workstation. One outlet must be supported by a four pair 100 ohm

UTP or ScTP (FTP) cable. Per the standard maximum of a Category 3 is required and a

Category 5 is recommended

Other outlets can be supported by any of the recognized media.

Distance Limitation UTP cable is limited to 295 feet (90 meters) in the

horizontal. Optical fiber is limited to 295 feet (90 meters) when

hub equipment is located in each telecommunications closet.

Optical fiber cable is limited to 984 feet (300 meters) when hub equipment is centrally located.

Distance Limitations Length of cable referred to in the distance

limitation is the jacketed length not the electrical length

Two lengths vary because of pair twists Telecommunications closet’s span is considered to

be a radius of 200 feet (60 meters) Horizontal cables follow pathways Slack

Service Loops It is recommended that a service loop of between 1-

3 feet of cable be left at all termination. This is to facilitate servicing those terminations.

Cabling Practices Connecting hardware must be installed in

compliance to local codes Bridged taps are not allowed UTP/ScTP (FTP) cable runs must be continuous,

without splices

Multi User Assembly and Consolidation Point Must be manageable in size

Serve 6 to 12 users Permanently located Work area cables clearly labeled Outlet to be marked with maximum allowable work

area cable length

Consolidation Points Only one consolidation point allowed in a horizontal

cable tun Cross-connections are not permitted at the

consolidation point Active equipment is not allowed at the

consolidation point. Each horizontal cable exiting the consolidation

point must have all four pairs terminated in the same modular jack.

Centralized Fiber Optic Testing Used in Fiber-To-The-Desk scenarios Horizontal runs with UTP are limited to 90m. Fiber has increased transmission distance

Horizontal cables can be installed directly to centralized “Hub Farms” within the building.

300 meter maximum distance. Three accepted methods

Pull through Through Splice Through Connect

EMI/RFI Cable routing, closet placement and drop locations

should be such as to avoid sources of EMI and RFI sources.

Detailed in standard EIA/TIA-569.

HORIZONTAL DISTRIBUTIONHORIZONTAL DISTRIBUTION

Conduit Types Recognized: Electrical metallic tubing Rigid metal conduit Rigid PVC

Conduit Type Not Recommended Metal Flex Conduit

Cable suffers from abrasion

Installation Guidelines Maximum run length without pull point 30 meters

(100 feet) Maximum of two 90 degrees bends between pull

boxes or pull points Fish tape or pull cord shall be placed in installed

conduit

Installation Guidelines Conduits protruding through the floor should

protrude in a Telco Closet should extend 1 to 4 inches (25-100 mm) above the finished floor

Conduits protruding through the floor in other areas should extend to 1 to 2 inches (25-50 mm) above the finished floor

Installation Guidelines Single conduit run extending from a

telecommunications closet shall not serve more than three outlets

Conduits shall be reamed Conduit shall be terminated with an insulated

bushing

Ceiling Pathways Ceiling distribution pathways be fully accessible

Drywall or plaster ceiling are not allowed Minimum of 3 inches (75 mm) is needed between

cable support hardware and the false ceiling. Same Distance is required between the hardware and the structural ceiling.

SEPARATIONSEPARATION

Pathway Separation Closed metal pathways provide adequate

protection from capacitively coupled (rapid changes in high voltages) in commercial buildings.

Closed metal pathways of ferrous induction suppression material shall be used in areas of high inductively coupled noise (rapid changes in high current).

Open or non-metal pathways shall be placed with sufficient separation.

Separation of Telco Path From </= 480V Power

Condition Minimum Separation Distance< 2 kva 2-5 kva > 5kva

Unshielded powerlines near open ornon metal pathways 5 in. 12 in. 24 in.

Unshielded powerlines near groundedmetal path. 2.5 in. 6 in. 12 in.

Power lines ingrounded metalconduit neargrounded metalconduit path. -- 3 in. 6 in.

SEPARATIONSEPARATION

High Voltage Separation Telecommunications cables should have a

separation of 10 feet (3 meters) from panels and power carrying voltages of 480 Vrms or greater.

Firestopping Properly rated firestop systems must be installed to

prevent or retard the spread of smoke, water, fire and gases through the building.

HORIZONTAL DESIGN HORIZONTAL DESIGN CONSIDERATIONSCONSIDERATIONS

BACKBONE DESIGN BACKBONE DESIGN CONSIDERATIONSCONSIDERATIONS

NETWORK CABLE NETWORK CABLE SOLUTIONSSOLUTIONSMODULE 4-EMODULE 4-E

BACKBONEBACKBONE

Backbone Planning Backbone cable plants should be designed to

accommodate the systems that are currently being used as well as those that will be in use in the future.

Planning should consider the changes that are anticipated in service requirements and system growth for a period of not less than 3 years and ideally up to 10 years.

Other factors that must be considered when a Backbone Cable Plant is being designed are:

Bandwidth requirements for present and future applications.

The number of Work Areas that are served by the backbone segment.

BACKBONEBACKBONE

Topology The backbone cabling plant must use the

hierarchical star topology. Two hierarchical levels of cross connects are

allowed in backbone cabling. Between the horizontal cross connect and the Main

cross connect only one cross connect may exist. No more than three cross connects between any

two horizontal cross connects. Limitation of two levels in hierarchy limits the size

of LAN. In large installations (I.e. universities, military

bases) the area should be segmented into smaller components and then interconnected.

BACKBONEBACKBONE

Location Main and intermediate cross connects are to be

located in Telecommunications Closets, Equipment Rooms, or Entrance Facilities.

Main cross connects Ideally located in an equipment room Ideally located in the geographic center of the area it

serves.

BACKBONEBACKBONE

Recognized Backbone Cable Types 100 ohm UTP/ScTP four pair cable. 100 ohm UTP multipair cable. 150 ohm STP cable. 62.5/125 or multimode optical fiber cable. Singlemode optical fiber cable.

BACKBONEBACKBONE

Composite and Hybrid Cables In backbone applications it is acceptable to use

composite or hybrid cables as long as each individual cable under the shared sheath exhibits standards compliant performance.

Crosstalk requirements are more stringent than for individual cables.

BACKBONEBACKBONE

Media Selection UTP and/or ScTP cables may be used in backbone

cable segments that do not exceed 295 feet (90 meters) for Category 5 applications.

Segments that are in excess of 295 feet (90 meters) should utilize optical fiber cables.

BACKBONEBACKBONE

Media Selection Fiber Optic Cable

The selection of fiber optic cable assures that high speed data applications will be supported in the backbone.

Fiber optic cable also has higher bandwidth in less pathway space than copper media.

Fiber optic cable is immune to the effects of RFI and EMI.

All dielectric fiber optic cables are immune to ground loops.

BACKBONEBACKBONE

Growth Recommendation is that one fiber pair be provided

for each current application and a 100% growth factor to be added to the fiber count.

BACKBONEBACKBONE

Distance Limitations It is important to note that not all current

applications will operate properly over lengths allowed by the standards for the copper media.

The standards allowed UTP cable lengths are based on voice applications. Backbone cable cannot exceed 295 ft (90 m) for applications with bandwidths equal to or greater than 4 MHz.

BACKBONEBACKBONE

Patch Cords In applications where bandwidths are less than 4

MHz, patch cords and jumpers in the Main Cross connect and Intermediate Cross connect shall be less than or equal to 66 ft (20 m).

In applications where bandwidths are equal to or greater than 4 MHz, the patch cords and jumpers are limited to 16 ft (5m).

BACKBONEBACKBONE

Planning If requirements are unknown, plan for one copper

pair for every 100 sg ft (10 sq m) If requirements are known, plan for copper pairs for

each 2 pair application and 8 pairs for each 4 pair application

Provision for growth and back up Provide 4 fibers for each 2 fiber application

BACKBONEBACKBONE

Service Loops Backbone cables terminating at a Horizontal cross

connect should have a 10 feet (3 meter) service loop

Backbone cables terminating at the main cross connect or at intermediate cross connects should have at least 33 feet (10 meters) service loops

BACKBONEBACKBONE

Design considerations discussed in the Horizontal Section EMI/RFI Separation Pathways Firestopping

BACKBONE DESIGN BACKBONE DESIGN CONSIDERATIONSCONSIDERATIONS

THANK YOUTHANK YOU

1 shielded cable performance parameters network cable solutions module 2-j

pair cable

shielding performance

overall shield construction

performance specifications

j slide

shield continuity

basic construction

overall foil shield

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