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Copper
Media
Copper
cable is used in almost every LAN. Many different types of copper
cable are available, with each type having advantages and disadvantages.
Proper selection of cabling is key to efficient network operation.
copper carries information using electrical current,
Cable Specifications:
Cables have different specifications and expectations pertaining
to performance:
• Speeds for data transmission(affected by the kind of conduit
used.)
• Kind of transmission being considered(Digital or baseband
transmission and analog-based or broadband transmission are
the two choices. )
• The distance a signal can travel through a particular type
of cable before attenuation of that signal. (Will the signal
become so degraded that the recipient device might not be able
to accurately receive and interpret the signal by the time the
signal reaches that device? Attenuation refers to the resistance
to the flow of electrons and why a signal becomes degraded as
it travels along the conduit.)
Coaxial cable technology is well known. It has been used for
many years for many types of data communication, including cable
television. Coaxial cable consists of a hollow outer cylindrical
conductor that surrounds a single inner wire made of two conducting
elements. For LANs, coaxial cable can be run longer distances
without the need for regenerating the signals in a network.
Some examples of Ethernet specifications which relate to cable
type include:
• 10BASE-T
• 10BASE5
• 10BASE2
10BASE-T refers to the speed of transmission at 10 Mbps. The
type of transmission is baseband, or digitally interpreted.
The T stands for twisted pair.
10BASE5 refers to the speed of transmission at 10 Mbps. The
type of transmission is baseband, or digitally interpreted.
The 5 represents the capability of the cable to allow the signal
to travel for approximately 500 meters before attenuation could
disrupt the ability of the receiver to appropriately interpret
the signal being received. 10BASE5 is often referred to as Thicknet.
Thicknet is actually a type of network, while 10BASE5 is the
cabling used in that network. Thicknet cable is almost never
used anymore, except for special purpose installations.
10BASE2 follows the same naming sequence(200 meters).10BASE2
is often referred to as Thinnet. Thinnet is actually a type
of network, while 10BASE2 is the cabling used in that network.
Shielded twisted-pair cable (STP) combines the techniques of
shielding, cancellation, and twisting of wires. Each pair of
wires is wrapped in metallic foil. The four pairs of wires are
wrapped in an overall metallic braid or foil. It is usually
150-Ohm cable. As specified for use in Ethernet network installations,
STP reduces electrical noise within the cable such as pair to
pair coupling and crosstalk. STP also reduces electronic noise
from outside the cable, for example electromagnetic interference
(EMI) and radio frequency interference (RFI).
Unshielded twisted-pair cable (UTP) is a four-pair wire medium
used in a variety of networks. Each of the 8 individual copper
wires in the UTP cable is covered by insulating material. In
addition, each pair of wires is twisted around each other. This
type of cable relies solely on the cancellation effect produced
by the twisted wire pairs, to limit signal degradation caused
by EMI and RFI. To further reduce crosstalk between the pairs
in UTP cable, the number of twists in the wire pairs varies
Additional
Resources on the Internet
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