Information Technology Reference
In-Depth Information
The telecommunications room is another important area in the chain of wiring
devices that makes up a structured LAN wiring installation. The
telecommunica-
tions room
(TR) is the point of termination of all of the “horizontal run” cables that
go from the TR to the workstation areas as well as the cables that interconnect to
other TRs. The TR typically contains the punchdown blocks, patches (Chapter 8),
and other termination and wire-routing devices necessary for the interconnection of
horizontal and backbone cabling. It may also contain various types of equipment,
such as wiring hubs, routers, and even network servers. All the wiring termination
methods and devices described in this chapter apply as well to similar wiring facili-
ties, including the main cross-connect, intermediate cross-connect, equipment room,
and entrance facility.
In the generalized model of universal, structured cabling, the TR also may con-
tain telephone switching and distribution equipment. Much of what we cover in this
chapter will be equally applicable to telephone wiring, but we will emphasize the
LAN wiring aspects wherever possible. It is interesting that the TR is one place
where the differing needs of telephone and LAN wiring are most apparent.
The very strict length and workmanship guidelines that are required for a
successful LAN wiring system are very much relaxed if you are installing tele-
phone wiring. For example, telephone wiring is often run through multiple sets of
punchdown blocks in several wiring closets with little regard to total distance or
care in routing. (Although the TIA standards do have strict guidelines, they are
often excessively strict for telephone connections.) The much lower audio fre-
quencies of most telephone installations allow these signals to run thousands of
meters on very loosely twisted pairs. However, if you intend for your wiring sys-
tem to be general purpose, so that you can run either voice or network signals,
you must design your system to meet the more stringent operating rules embod-
ied in the TIA or similar ISO standards. LAN wiring requires strict adherence to
length, routing, rating, and workmanship rules to operate properly. The extra
requirements for LAN operation are really the determining factors in the design
of a modern structured wiring system.
In this chapter, we will cover all of the types of termination and routing
devices, except patch panels, that are used in the TR. Patch panels, jumpers, and
cross-connects are covered in the next chapter. In higher-category cabling systems,
it is very common to terminate horizontal cables directly into a patch panel.
However, the termination blocks used will very likely be a variation of the 110-style
connecting block described in this chapter. In addition, we will also cover some of
the mounting and location issues of the TR, including the options for locating hub
equipment.
