Information Technology Reference
In-Depth Information
The next step in structured cabling is the interconnection of cabling in the telecom-
munications room (TR). As we will see, patch panels, patch cords, and cross-con-
nect jumpers form a vital part of LAN wiring. Patch panels may be used as the
primary termination for horizontal and backbone cabling, in lieu of punchdowns
(described in the previous chapter). As a matter of fact, patch-panel termination is
becoming increasingly popular with advanced performance categories, such as
Category 5e, 6, AC6, and 7. It is the only practical means of termination for
Category 7, although that “patch” actually consists of an array of Cat 7 connectors.
Fiber termination is also done with the same type of patch-array, utilizing a cabling
“adapter” to secure the connectors and align the fibers.
In this chapter, we will describe the wiring, cables, and devices used for patch
panels, patch cords, and cross-connects, for both fiber and copper cabling systems
designed for LAN use. In the last chapter, we covered the actual termination of the
station cables into punchdown blocks in the TR. We did not yet cover the cross-con-
nect wiring or jumper cables. In addition, although we have mentioned the wiring
method of terminating horizontal cables directly into patch panels, we have waited
until now to describe the patches themselves.
Traditionally, there has been an ongoing debate about the alternatives of patch pan-
els and cross-connects. Figure 8.1 shows the two alternatives to cable termination
and the interconnection to equipment in the TR.
Traditional Cross-Connect Termination
The first alternative shown in the figure copies the cross-connect methodology used
for traditional telephone equipment room wiring. In this method, horizontal (sta-
tion) cable is terminated on a connecting block, such as a 110 or 66 block. Then,
cross-connect wires are run from each station position on the horizontal connecting
blocks to a second field of connecting blocks, which is a point of termination for
multipair cables from the common equipment such as a telephone switch or PBX.
This common equipment connection in a telephone system corresponds to the net-
work hub connection in a local area network (LAN).
The common equipment connections and the station cable connections are
rather like the input/output of the cross-connect field. Both types of cables are hard
wired to the connecting blocks and then cross-connected with unjacketed wire pairs
called
jumpers
. To make a connection across the field, a cross-connect jumper (con-
