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Management Information Systems

Notes
Figure 6.8: RJ-45 Connectors

When used as a networking medium, UTP cable has four pairs of either 22- or 24-gauge copper
wire. UTP used as a networking medium has an impedance of 100 ohms; this differentiates it
from other types of twisted-pair wiring such as that used for telephone wiring, which has
impedance of 600 ohms.
UTP cable offers many advantages. Because UTP has an external diameter of approximately 0.43
cm (0.17 inches), its small size can be advantageous during installation. Because it has such a
small external diameter, UTP does not fill up wiring ducts as rapidly as other types of cable. This
can be an extremely important factor to consider, particularly when installing a network in an
older building. UTP cable is easy to install and is less expensive than other types of networking
media. In fact, UTP costs less per meter than any other type of LAN cabling. And because UTP can
be used with most of the major networking architectures, it continues to grow in popularity.
Disadvantages also are involved in using twisted-pair cabling, however. UTP cable is more
prone to electrical noise and interference than other types of networking media, and the distance
between signal boosts is shorter for UTP than it is for coaxial and fiber-optic cables.
Although UTP was once considered to be slower at transmitting data than other types of cable,
this is no longer true. In fact, UTP is considered the fastest copper-based medium today. The
following summarizes the features of UTP cable:
1. Speed and throughput-10 to 1000 Mbps
2. Average cost per node-Least expensive

3. Media and connector size-Small
4. Maximum cable length-100 m (short)
Commonly used types of UTP cabling are as follows:

1. Category 1 – Used for telephone communications. Not suitable for transmitting data.
2. Category 2 – Capable of transmitting data at speeds up to 4 megabits per second (Mbps).
3. Category 3 – Used in 10BASE-T networks. Can transmit data at speeds up to 10 Mbps.
4. Category 4 – Used in Token Ring networks. Can transmit data at speeds up to 16 Mbps.
5. Category 5 – Can transmit data at speeds up to 100 Mbps.

6. Category 5e – Used in networks running at speeds up to 1000 Mbps (1 gigabit per second
[Gbps]).
7. Category 6 – Typically, Category 6 cable consists of four pairs of 24 American Wire Gauge
(AWG) copper wires. Category 6 cable is currently the fastest standard for UTP.

Shielded Twisted Pair (STP) Cable

Shielded twisted-pair (STP) cable combines the techniques of shielding, cancellation, and wire
twisting. Each pair of wires is wrapped in a metallic foil (see Figure 6.9). The four pairs of wires
then are wrapped in an overall metallic braid or foil, usually 150-ohm cable. As specified for
use in Ethernet network installations, STP reduces electrical noise both within the cable

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