Information Technology Reference
In-Depth Information
T568A Jack
T568B Jack
1
W/G
G
1
W/O
O
Pair 3
Pair 2
2
2
W/O
W/G
3
3
B
B
4
4
Pair 1
Pair 1
Pair 2
Pair 3
W/B
W/B
5
5
6
O
6
G
7
W/Br
7
W/Br
Pair 4
Pair 4
8
Br
8
Br
8-pin modular jack
(front view)
8-pin modular jack
(front view)
FIGURE 3.1
The T568A and T568B wiring patterns.
TIA-568 Uses
The TIA-568-C standard defines many wiring structures that apply to all telecom-
munications wiring, including traditional telephone system wiring. The hierarchy of
these wiring structures is shown in Chapter 14. Although the standard creates a very
serviceable telephone wiring system, the real need lies in LAN applications, which
are much pickier about transmission characteristics. The portions of the standard
that apply particularly to LAN wiring restrict such things as the length of cable and
cross-connects, the characteristics of the cable, and installation techniques.
If you use the TIA-568-C system for a LAN, you may need to restrict the wiring
to a particular category, such as Category 5e or 6. This will place additional require-
ments on your wiring, such as the maximum cable run, the type of cable, the amount
of untwist, and number of cross-connect (punchdown) points that are acceptable.
The benefit to you is that your cabling system will not only support your current
LAN requirements, but will likely support future LAN generations and technology.
Figure 3.2 shows a summary of the characteristics for TIA-568-C cabling.
Standard wiring patterns for the plugs, jacks, punchdown blocks, and patch panels
are used for the TIA-568-C system. Refer to Chapters 5, 6, and 7 for these details.
The Avaya/Lucent Technologies (AT&T) Premises Distribution System (PDS) is a
wiring system that bears great similarity to the TIA-568-C system.
The original PDS system, however, is basically a multipurpose telecommunica-
tions wiring system that can also be used for LANs. In contrast, the 568/UTP
system is primarily designed with LANs in mind, but can also be used for telecom-
munications.
