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Guide to Network Cabling Fundamentals

Chapter 6

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Chapter 6 - Cable Termination and Splicing

Name the various locations for cable termination Splice wire and cable Discuss the “tools of the trade” for cable termination Understand the color codes and wiring schemes

used for cable termination Terminate cable Document network hardware

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Terminating cable: Happens after completion of the system design,

selecting and running cable, and implementing all necessary grounding and bonding

An important place to terminate cables is the network interface, the demarcation point, or demarc for short; it is here that control or ownership of the communications facilities changes from the service provider’s equipment to the customer’s

Cables must also be terminated in the equipment room, the TRs, and the work areas

Locations for Terminating Cable

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Network interface devices and demarcation points are governed by the FCC’s Rule 68 Rule 68 was designed to ensure that customer equipment

and wiring could be connected to the Telco network without causing harm

Network interface devices are the equipment used to terminate cable at demarcs

The number of pairs used in the Telco and customer cables is the primary factor in selecting equipment for cable termination at the demarc

Locations for Terminating Cable

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Small systems include homes and businesses that have one to six phone lines or cable pairs Network interface devices for small systems are boxes

usually made of high-impact, waterproof plastic, consisting of two sections

One section is used to terminate the Telco cables, including a connecting block with two screw terminals, a standard modular jack, an earth ground connection, and a protector; the other section is used for terminating customer wiring, consisting of a terminal strip and a standard modular plug

Locations for Terminating Cable

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Large systems include large companies and commercial buildings that can have several hundred phone lines or cable pairs Network interface devices for large systems include a number

of components, with the primary one being a punch-down block, a rectangular block of plastic with metal connectors that are split through their center and embedded in plastic

The two most common types of punch-down blocks are 50-pair 66-types and 50-pair M110-types

Other components include protectors and a wood backboard for indoor installations

Locations for Terminating Cable

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Equipment rooms and telecommunications rooms contain cable terminations, and in either case, the same termination equipment is used In equipment rooms, there is usually backbone cabling to

terminate and cross-connect to telecommunications equipment; sometimes this cabling is also the demarcation point for the building and there is a need to terminate and cross-connect these to the telecommunications equipment

In TRs, generally there is a need to terminate and cross-connect only horizontal and backbone cables

Locations for Terminating Cable

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Equipment rooms and telecommunications rooms (cont.): Two common methods are used for terminating cables in

these rooms The first method is to terminate the cables on punch-down

blocks that are wall-mounted on wood panels The second method is to terminate the cable on rack-

mounted patch panels with punch-down block on the back for cables and modular receptacles on the front for plugging in patch cords

Wire wrapping is an additional method used

Locations for Terminating Cable

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Work areas: Cable termination in work areas requires terminating the

horizontal cable to a telecommunications outlet (jack), which provides the interface between the telecommunications equipment and the cables

A telecommunications cord provides the interface between a piece of telecommunications equipment and a telecommunications outlet

There are literally thousands of telecommunications outlets from which to choose

Locations for Terminating Cable

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Telecommunications Outlets Telecommunications outlets are available in configurations

of 2-pair, 3-pair, and 4-pair Jack designs available are flush- and surface-mount Cable-connecting interfaces either use screw terminals or

M110-type connectors

Telecommunications Cords Also called silver satin cords, these cords are made of

filament-like strands of copper wires that are twisted together around a cotton-like material

Fiber termination plugs are built differently

Locations for Terminating Cable

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A splice connects two wires, fibers, or cables Splicing is used to solve cabling problems and requires

special equipment and tools The three primary methods of splicing copper wires are

soldering, single-wire solderless crimping, and multiwire solderless connecting

To make solderless, single-wire splice connections, use B-wire or Scotchlok connectors; for multiwire (connecting 25 pairs at a time), use and insulation displacement connector (IDC) and protect these splices in a splice enclosure

Splicing Wire and Cable

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Splicing (cont.): A final method of splicing copper is a measure called

twist and tape, where bare copper ends are twisted together and the connection is covered with electrical tape; this is used only in emergencies

Fiber-optic splicing is the joining of two fiber cables using mechanical or fusion splicing

Mechanical splicing uses a simple aligning device to hold two ends of fiber together precisely

Fusion splicing uses a machine that precisely aligns the two ends, then welds them together

Splicing Wire and Cable

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Splicing (cont.): Prices play a key role in choosing a fiber splicing

method: mechanical has a low initial investment, but the cost per slice is high; fusion’s equipment costs are high, but cost per splice is very low

A cleaver is the most valuable tool for fiber splicing To ensure the quality of fiber splices, clean tools

frequently, avoid dirt, check machine parameters Always make safety the first priority when installing,

maintaining and repairing fiber; attend fiber-optic safety training

Splicing Wire and Cable

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Many tasks of a telecommunications specialist require tools that are specifically designed Telephone line testers test lines, jacks, and circuits Impact tools, known as punch-down tools, are used for

connecting wires to 66- or 110-type terminals Tone generators and inductive amplifiers help locate

wires; the tone generator, when connected to a pair of wires, emits a sound you can hear through the speaker of the inductive amplifier when the probe tip passes over the wires

Tools of the Trade

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Specifically designed tools (cont.): Cable stripper and crimp tools put plugs on cables Use the cable stripper to remove the cable sheath and

expose the wires inside Use the crimp tool to squeeze the contacts in the

modular plug so they make permanent contact with the wires and secure the plug onto the cable

Bridging clips connect right- and left-side punch-downs; cable ties secure cables to racks or poles

Other tools: screwdrivers, needle-nose pliers, cable tester, soldering iron, electrical tape, sponge

Tools of the Trade

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Color code: 25 color designations define how cables are connected;

the color code is separated into two parts called the tip and the ring

The tip is the ground or common wire and is the first part of the color code; the ring provides the voltage and is the second part of the color code

Wiring Schemes The EIA/TIA created 568-A and 568-B standards to

define the wiring configurations for 4-pair Category 5 cable terminated in RJ-45 modular plugs

Color Codes and Wiring Schemes Used for Cable Termination

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Terminating cables: The first step is to connect the cable(s) at the network

interface, or demarc, for both small- and large-system network interface devices

The next step involves terminating cable in equipment rooms and telecommunications rooms

Terminating cables in the work area is the last step Terminating fiber-optic cable is different from terminating

copper cable Popular fiber connectors: ST, SC, LC, MT-RJ

Color Codes and Wiring Schemes Used for Cable Termination

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The next part of the documentation manual should cover all of the network hardware Documenting internetworking devices should include

hubs, switches, and routers Documenting servers should describe the server’s

hardware configuration and operating system, available services, resource configurations and limitations, administrative contacts, and server documentation tools

Documentation for workstations should be similar to the server documentation

Documenting Network Hardware

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Chapter Summary

Cable termination is the process of connecting cables to workstation outlets, connecting blocks, and cable connectors. Several locations in every telecommunications system require cable termination, including the network interface, or demarcation point, the equipment rooms and telecommunications room, and the work areas. The connecting devices and tools you use to terminate cable depend on the cable’s location and type

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Chapter Summary

The demarcation point is where control or ownership of the communications facility changes from the Telco equipment to the customer-provided equipment. FCC Rule 68 requires demarcation points to ensure that customer equipment and wiring can be connected to the Telco without causing harm. Network interface devices, the equipment used to terminate cable at the demarcation points, permit all customer equipment and wiring to be disconnected from the Telco wiring for testing and maintenance

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Chapter Summary

Network interface devices generally fall into one of two categories: those used for small systems and those used for large systems. Small systems include residences and small businesses that have one to six telephone lines or cable pairs. Large systems include large companies and commercial buildings with multiple tenants; these buildings and companies can have several hundred telephone lines or cables

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Chapter Summary

Equipment and telecommunications rooms require termination of backbone, horizontal cross-connect and cabling. The termination methods are similar for all three types of cabling; only the actual equipment and required tools may differ, depending on the media type being terminated. In these rooms, you can terminate cables by mounting the equipment on walls or by using racks and patch panels

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Chapter Summary

Work area terminations involves wiring the horizontal cabling to the telecommunications outlets (jacks)

Splicing is the process of making permanent connections between wires, cables, or fibers. Splicing is commonly used to extend the length of a cable, or to repair a break or a cut

Telecommunications professionals use a variety of specialized tools, including telephone line testers (butt sets), impact tools, cable strippers, cable-crimping tools, tone generators and inductive amplifiers (toners and tracers), and bridging clips

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Chapter Summary

The color code is crucial information for a telecommunications professional. Every type of wiring and termination is based on the color code

Network hardware documentation includes the servers and workstations in a network, as well as all internetworking equipment such as hubs, switches, and routers. Complete hardware documentation makes troubleshooting easier and helps you determine when upgrades and design changes are necessary