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Telecom Cabling

Telecommunications cable types

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Telecom Cabling

Cable types: Quad or JK.

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Telecom Cabling

Quad cable is a typical residential style cable.

It may also be called “JK” cable.

It is called quad cable because it contains four conductors.

The four conductors are color coded as Green, Red, Black, and Yellow.

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Telecom Cabling

There are times when it will be necessary to incorporate 4 pair UTP into a quad style outlet or plug.

The next slide shows multiple ways of terminating plugs using 4 pair and quad.

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Telecom Cabling

Pin outs for UTP and Quad

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Telecom Cabling

Note the use of “T” and “R” when discussing telephone circuits.

A telephone is simply a circuit like a battery. It has a Positive (+) and a Negative (-) part.

In telephony we use tip (T) to show positive and ring (R) to show the negative side of the circuit.

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Telecom Cabling

Pin-outs RJ-11. Note that the center pins of a plug carry telephone signal.

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Telecom Cabling

When simple premise is color coded, two-wire telephone plugs or the first pair of a multi-pair plug commonly have the tip wire coded green and the ring coded red.

In four wire plugs, the second pair is black (tip) and yellow (ring).

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Telecom Cabling

For a third pair, white (tip) and blue (ring).

For larger numbers of wires, more complex schemes such as the 25-pair color code are used.

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Telecom Cabling

Residential Color Code (USOC), uniform service order code.

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Telecom Cabling

Green before Red, Black before YellowChristmas and Halloween.

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Telecom Cabling

How would we wire 4 pair UTP (blue, orange, green, and brown) to a quad style jack?

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Telecom Cabling

Answer: white/ blue to green, blue/white to red, white/orange to black, and orange/ white to yellow.

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Telecom Cabling

STP cable (shielded twisted pair).

4 pair cable with an overall foil shield and each pair is shielded.

Used in areas where interference can occur (e.g. a machine shop) or T1s.

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Telecom Cabling

STP cable, notice it has a small metallic wire.

This small metallic wire is called the drain wire and is usually ground to the patch panel.

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Telecom Cabling

Note that with shielded cable we must use a shielded jack and a shielded patch panel as well.

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Telecom Cabling

In some instances we install a screened cable called ScTP, this also has a drain wire.

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Telecom Cabling

1- conductor2-insulation3-cable jacket or sheath

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Telecom Cabling

Cable construction:

A typical cable is constructed with copper conductors which are covered with insulation and are then covered with a jacket or sheath with a rip-cord inside the jacket as well.

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Telecom Cabling

How do you know what type of cable you have?

The cable jacket is labeled every 4 feet.

This is important information for the installer.

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Telecom Cabling

Because cables installed in a building can be a source of toxic fumes and flame spread during a fire, the type of material used in the jacket and insulators is important.

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Telecom Cabling

It is so important that it is regulated by several government agencies and we are required by law to install the correct cable type in the correct place.

Lets look at the types of cable jackets we use in our industry.

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Telecom Cabling

There are essentially three areas into which we install our cables:

PLENUM CMP (P denotes plenum)

NON-PLENUM (general purpose) CM

RISER CMR (R denotes riser)

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Telecom Cabling

WHAT IS A PLENUM?

A separate space provided for return air circulation for heating, ventilation, and air-conditioning

Typically provided in the space between the structural ceiling and a drop-down ceiling.

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Telecom Cabling

A plenum may also be under a raised floor. In buildings with computer installations, the plenum space is often used to house connecting communication cables.

Because ordinary cable introduces a toxic hazard in the event of fire, special plenum cabling is required in plenum areas.

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Telecom Cabling

Plenum cable is usually about 3 times more expensive than non-plenum cables.

This a huge consideration when installing cables.

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Telecom Cabling

In the U.S., typical plenum cable sizes are American Wire Guage (AWG) sizes 22, 23 and 24.

Plenum cabling is often made of Teflon and is more expensive than ordinary cabling.

In the event of fire, its outer material is more resistant to flames and, when burning, produces less toxic smoke than ordinary cabling.

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Telecom Cabling

Here we see cable designations:The white cable indicates that it is a CAT 5 patch cord.The yellow cable is type CMP and the pink cable is CM.

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Telecom Cabling

RISER-used in vertical tray applications such as cable runs between floors through cable risers or in elevator shafts.

These spaces cannot be used for environmental air.

These cables must self extinguish and must also prevent the flame from traveling up the cable in a vertical burn test.

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Telecom Cabling

Cables used in vertical riser shafts must have the CMR listing.

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Telecom Cabling

Some high pair count cables (100 to 2400 pr.) may be PIC (plastic insulated cable) types.

This type of cable has a 25 pair color code with no tracers so it is very important to not let the pairs untwist.

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Telecom Cabling

General Purpose -Will burn and partially self extinguish.

Not for use between build floors or in air plenum spaces.

Often these cables are used for workstation cables and patch cords.

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Telecom Cabling

Can CMP cable be substituted with CMR cable for horizontal runs?

Can CMR cable be substituted with CMP for use in vertical riser shafts?