Information Technology Reference
In-Depth Information
FIGURE 1.2
Structured wiring covers the cable runs from start to finish.
mum distances, types of connections, grade of cable and connectors, and installa-
tion practices necessary to provide a reliable and flexible data and voice cabling
infrastructure. The embodiment of modern structured data/voice wiring is the
TIA/EIA-568-C standard for North America and the ISO/IEC 11801 standard for
the European Community. For the most part, the balance of the countries around
the world use one of these standards for their local cabling guidelines. Fortunately,
these primary standards are becoming more and more coordinated through a
process of international technical cooperation called harmonization .
The next few sections describe the major wiring strategies of horizontal and
backbone cabling. Horizontal wiring takes the bulk of our attention in LAN wiring ,
as it is the most complex structure, and offers the most challenges to designer and
installer alike.
Horizontal Wiring Structure. The basic component of the structured wiring sys-
tem is the horizontal wiring (cabling) structure. Horizontal cabling consists of the
cable and connections from the wall or other jack at the user workstation outlet to
the wire termination in the TR. As shown in Fig. 1.3, the horizontal wire may
include a punchdown block, cross-connect wire, and a patch panel. However, it
does not include hubs, routers, or network adapters.
Horizontal cable is defined in TIA/EIA-568-C “Commercial Building
Telecommunications Wiring Standard,” and is the Permanent Link (minus cross-con-
nect and test cables) originally defined in TSB-67, “Transmission Performance
Specifications for Field Testing of Unshielded Twisted-Pair Cabling Systems.” In prac-
tice, horizontal wire is routed directly from the TR to the workstation, without any
intermediate splice points, cable junctures, or taps, as might be common practice in
traditional telephone wiring. This direct-wiring technique is referred to as a home run .
Various wiring standards put special qualifications on horizontal wiring. Some
of these may limit the types of components, such as cross-connects, that may be a
part of horizontal wiring. More specifically, you should make sure that you use
cable and components that are rated for the data rates you intend to use. For exam-
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