Information Technology Reference
In-Depth Information
Figure 8.1
Four basic types of wires.
next to each other in the same configuration throughout the length
of the cable. For convenience in identifying each metallic wire, the
insulation for each wire has a different color. In using this wire, cir
cuits often utilize pairs of wires, typically red and green for one cir
cuit and black and yellow (sometimes blue and white) for the sec
ond circuit. Because these wires run next to each other, these
circuits are said to utilize
untwisted pairs
of wires.
The right middle cable in Figure 8.1 contains four pairs of wires,
and the metallic wires in each pair are twisted together. This aspect
of their design has a specific purpose. Transmission of signals along
