Communication
Channel
Physical Transmission media
In physical Transmission
media, communication devices are directly linked with each
other via cables or other physical materials for data
communication. These are also referred to as wired channels.
The physical transmission media are usually used in LAN.
There are three main medium
of transmission are:
- Twisted-Pair Cable
- Coaxial Cable
- Fiber-Optic Cable
Twisted-Pair Cable
It
is one of the most commonly used communication media for network
cabling. It consists of two separate copper wires that are
covered by insulating material such as plastic and twisted
together to form a cable. The wires are twisted together to
reduce the noise. The noise is created due to high-voltage
equipment or due to light energy of sun.
The telephone cable wiring at home uses twisted-pair wire, so
this type of wire is often called the telephone wire. The data
transmission speed of twisted pair is 10 Mbps to 100 Mbps or up
to 1 Gbps.
Coaxial Cable
Coaxial Cable is also referred to as coax. It consists of a
single copper wire surrounded by insulating materials. Usually,
it is surrounded by three layers.
The
coaxial cable is widely used in cable television systems. It is more
expensive than twisted-pair wire. The main advantages of coaxial cable
are, it creates less noise and protects the cable from interference of
external electromagnetic waves. These cables can transmit data over
longer distances than that of twisted pair.
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