Page 825 - (ISC)² CISSP Certified Information Systems Security Professional Official Study Guide

transmitted over one set of wires is picked up by another set of wires
due to radiating electromagnetic fields produced by the electrical

current. Each wire pair within the cable is twisted at a different rate
(in other words, twists per inch); thus, the signals traveling over one
pair of wires cannot cross over onto another pair of wires (at least
within the same cable). The tighter the twist (the more twists per
inch), the more resistant the cable is to internal and external
interference and crosstalk, and thus the capacity for throughput (that
is, higher bandwidth) is greater.

There are several classes of UTP cabling. The various categories are
created through the use of tighter twists of the wire pairs, variations in
the quality of the conductor, and variations in the quality of the
external shielding. Table 11.9 shows the original UTP categories.

TABLE 11.9 UTP categories

UTP Throughput Notes
category

Cat 1 Voice only Not suitable for networks but usable by
modems

Cat 2 4 Mbps Not suitable for most networks; often
employed for host-to-terminal connections
on mainframes

Cat 3 10 Mbps Primarily used in 10BaseT Ethernet
networks (offers only 4 Mbps when used on
Token Ring networks) and as telephone
cables

Cat 4 16 Mbps Primarily used in Token Ring networks

Cat 5 100 Mbps Used in 100BaseTX, FDDI, and ATM
networks

Cat 6 1,000 Mbps Used in high-speed networks

Cat 7 10 Gbps Used on 10 gigabit-speed networks

Cat 5e is an enhanced version of Cat 5 designed to protect