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Unformatted text preview: compared to coaxial
It is made up of four pairs of wires that
are twisted around each other and
then sheathed in a insulator.
If there is a metal foil wrapper around
the wires underneath the external
sheath, the wire is known as shielded
Lecture-3 38 Communications and Network Security …cont. The twisting of the wires provides protection from
external radio frequencies and electric and magnetic
interference and reduces crosstalk between pairs. Crosstalk occurs when data 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 (i.e., twists per inch); thus, the signals traveling over
one pair of wires cannot cross over onto another pair of
wires. The tighter the twist (the more twists per inch), the more
the cable is to internal and external interference and
crosstalk and thus the capacity for throughput (that is,
higher bandwidth) is greater.
Lecture-3 39 Communications and Network Security …cont. Lecture-3 40 Communications and Network Security …cont. The following problems are the most
common with twisted-pair cabling:
Using the wrong category of twistedpair cable for high-throughput
Deploying a twisted-pair cable longer
than its maximum recommended length
(i.e., 100 m).
Using UTP in environments with
Lecture-3 41 Communications and Network Security …cont. Conductors
The distance limitations of conductorbased network cabling is due to the
resistance of the metal used as a
Copper, the most popular conductor, is
one of the best and least expensive
room-temperature conductors available.
It is resistant to the flow of electrons.
This resistance results in a degradation
of signal strength and quality over the Communications and Network Security …cont. Conductors
The maximum length
defined for each cable type
indicates the point at which
the level of degradation could
begin to interfere with the
efficient transmission of data.
Lecture-3 43 Communications and Network Security …cont.
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This note was uploaded on 01/21/2014 for the course IT 205 taught by Professor Kurts during the Winter '08 term at University of Phoenix.
- Winter '08