Information Technology Reference
In-Depth Information
Transmission Mode (ATM) Forum specify twisted-pair wiring for the medium.
These new connectivity options range in speed from 25 Mbps to 155 Mbps and use
the TIA/EIA-568-C 90 m (295 ft) horizontal cable link as the model. Some high-
speed networking proposals use two pairs, while others use four pairs. The higher
speeds may require the use of premium Category 5e cable and connecting hardware,
but they still operate on conventional metallic twisted-pair cable. Clearly, twisted-
pair wiring has a lot to offer for the future of networking.
Structured Wiring
Structured wiring based on the standards (such as TIA/EIA-568-C) assumes that the
total wiring system will be divided into simple wiring units. These wiring units can
be repeated as needed, combined into larger structures, and those structures inter-
connected to produce the overall wiring system. Although some standards exist for
implementing particular LAN topologies, such as 10/100BaseT, over a wiring sys-
tem, most of the standards simply require a generic, multipurpose, reusable wiring
and cabling system that could be used for anything from voice to video. Of course,
these standards are designed to allow LAN traffic to properly operate at specific
data rates, and specify test parameters to ensure performance. However, the stan-
dards for the cabling itself are not at all specific to any type of LAN.
This is an enormous advantage to you, as the cable system designer, installer,
or LAN manager. If you install a standards-based structured wiring system, you do
not need to know anything at all about the exact type of LAN that will be installed
in your wiring system. All you do need to know is what data rate will be expected
of the LAN, because that will define the category of cable that must be used.
The most significant standard in LAN wiring is the “ANSI/TIA/EIA-568-C
Commercial Building Telecommunications Wiring Standard.” Along with related
standards and bulletins, this standard defines a universal cabling system that meets
a variety of needs. The TIA is really the moving force behind this standard, although
it is approved by EIA and ANSI and coordinated with many national and interna-
tional standards. (By the way, one normally says the letters T, I, A individually,
though you could certainly say it as a word.)
Any type of voice, data, or LAN signals can be connected to your structured
cabling system. For example, the twisted-pair wiring system that is specified by
TIA/EIA-568-C will allow you to run analog or digital voice, 10BaseT Ethernet,
100BaseTX Ethernet, 100BaseT4 Ethernet, 1000BaseT, 100VG-AnyLAN,
LocalTalk/AppleTalk (TM), Arcnet, 4 Mbps Token-Ring, 16 Mbps Token-Ring, 100
Mbps Token-Ring, CDDI (Copper FDDI at 100 Mbps), and ATM at 25, 51, 155,
and 622 Mbps. Of course, integrated services digital network (ISDN), Switched 56
