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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 |
