Communication media refers to the physical materials that transmit data from one point to another. Examples include radio, television, telephone lines, cellular phones, satellites, and cables. Radio and television transmit electromagnetic signals to broadcast sound and images without wires. Cellular phones use radio signals transmitted through cellular towers to provide portable wireless communication services. Satellites relay radio signals over long distances to provide communication. The appropriate medium depends on the distance data must travel, with cables used for short distances and wireless technology for long distances.

1. COMMUNICATION MEDIA
Communication Media refers to the physical material along which data travels from one point to
another. Examples of Communication Medias are: radio, television, telephone lines, cellular
phones, satellites and cables.
Radio uses electromagnetic waves to transmit and receive information. This is used as a sound
broadcast or for two-way communication which does not use connecting wires.
Television receives and sends images and sounds by means of electronic signals which are
transmitted through wires and optical fibres or by electromagnetic radiation. These signals are
broadcast from a central source – a television station – to the television sets in houses or relay
stations (cable television service providers).
Telephone lines can use digital or analogue signals. The lines that carry digital signals are much
faster than those that use analogue signals. Digital signals allow computers faster access to the
internet and other online services.
Cellular phones, also called cellular radio telephones, are low-powered, lightweight cordless
phones. They are completely portable and do not require connection to a jack to function.
Cellular phones provide the services of videoconferencing, email and internet access. Most
recently they are being used as still cameras and video cameras. They operate by transmitting
radio signals to cellular towers. These towers can receive signals from distances of over 1.5
kilometers to 56 kilometers depending on their capacity. The area the tower covers is referred to
as a cell. Tower cells overlap and form a network. Cellular calls are picked up by the towers and
relayed to other cellular phone users or to a conventional wire-based telephone network. Due to

2. the convenience/mobility the fee paid for the service of a cellular phone is usually higher than
that of a conventional phone.
Satellites provide communication over long distances by reflecting or relaying radio-frequency
signals.
The medium you use is dependent on the distance the data has to travel. For computers that are
linked by cables (short distance communication), there are three choices: twisted pairs, coaxial
cable and fibre optic. For communication over long distances, wireless technology is necessary,
for example microwave and satellites.
Cables are used to link individual terminals to the host (CPU). They consist of twisted pairs of
copper or copper-coated sheet wires.