Information Technology Reference
In-Depth Information
stuck to the wall. These raceways are more appropriate for the self-contained sur-
face outlets.
A note of caution should be stated regarding these raceways and matching
boxes. The safety standards of the NEC and other agencies do not allow telecom-
munications wiring to share any raceway space or outlet box with Class 1 wiring.
Class 1 wiring is wiring for lighting or electrical power circuits, the typical line
power that supplies lights and electrical outlets. In some narrow cases, the wiring
may be allowed in the same outer raceway cover, but it must be separated by a spe-
cific type of partition. See the code books for a detailed explanation of when and
where this can be done. Bear in mind that the run-of-the-mill square power pole that
drops from a suspended ceiling to a work area rarely meets this test, even though
there is plenty of extra room inside for the telecommunications cable. Some modu-
lar furniture may have the same problem, as the wiring channel may be occupied by
Class 1 wiring. In such cases, you may have to run the telecommunications wiring
external to the wiring channel. Several varieties of multimedia (copper and fiber)
outlet boxes are shown in Fig. 6.6.
Modular Jacks for Twisted Pair
Modular outlet jacks for twisted-pair wiring have been around since modular con-
nectors were first introduced several decades ago. The first of these jacks had loose
wires from the connector to screw terminals mounted to the body of the connector
assembly. Because these jacks were for analog telephone use, at very low frequen-
cies, little consideration was given to the crosstalk and impedance issues that are
very important at today's higher frequencies. Jacks for LAN use are very different
from these old telephone styles.
In this section, we will describe the various types of jacks that are used for twisted-
pair LAN wiring. For our purposes here, the jack will include the modular connector
itself, the means of terminating a twisted-pair cable, and the wiring in between.
FIGURE 6.6
Examples of flush-mounted and surface-mounted multimedia (copper and fiber) outlet boxes.
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