Page 44 - Optical Switching And Networking Handbook

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Basic Fiberoptics Technologies 29

Unshielded twisted pairs of wire (although you can use
shielded)

100-ohm (100- ) cables
Solid conductors in the cabling (you can use stranded wires, but
solid conductor is more available)
24-gauge wire (24 AWG)
100 meters (328 feet)

Using these specifications, we then used the appropriate category
of wire to satisfy our need, as shown in the table.
As one can see, the use of the wire was limited to specific speeds
and applications within the LAN. When the industry decided to
extend the speeds and the boundaries of the LAN into a CAN, the
cabling systems became part of the problem. As a result, two differ-
ent competing techniques emerged to satisfy the demand: FDDI,
which supports 100-Mbps bursty data across a much larger area

Table 2-1
Category of Wire Speeds Supported and Design Techniques
Comparing What
Data Rates Can 1 Plain old telephone service (POTS) and EIA-232 data*
Be Achieved 2 4 megabits per second (Mbps) of bursty data as found in
Through Token Ring LANs
Categories of
3 10 Mbps of bursty data as found in Ethernet (10 base T)
Wire
4 16 Mbps of bursty data in Token Ring, 20 Mbps of
bursty data as found in ARCNet, and now 25.6 Mbps
ATM to the desktop
5 100 Mbps bursty data as found in the fast Ethernet
standard (100 base T) and copper data distributed inter-
face (CDDI)† and now 155 Mbps ATM to the desktop

*EIA-232 (or RS-232) was a specification that satisfied 19.2 kilobits per second (Kbps) of data
at 50 feet but was extended through the use of category 1 wires.
†This was a copper equivalent to the fiber distributed data interface (FDDI).