What is COMMUNICATION MEDIA

COMMUNICATION MEDIA

The medium(or media)is the matter or substance that carries the voice or data transmission.it can be copper (wire or coaxial cable), glass(fibre optical cable), or wave (microwave). A circuit (channel or line) is nothing more than the path over which data moves. COMMUNICATION MEDIA is of two types:

Guided/wired Media: In this type of media wired are used. It is further clarification into three categories:

(1) TWISTED PAIR CABLE:

*Made of copper, coated with insulation material and continuously twisted throughout its entire length.
*Twisted helps minimize the effects of noise or electromagnetic interference.
*Relatively inexpensive and easy to install.
*Low immunity of noise, narrow bandwidth.
*Data rates up to 20Mbps in LAN;19.2Kbps for long distance communications over the telephone network
* Readily available in existing buildings.
* Usage      -. Voice communications
                   -. Data Communication e.g., telephone.

(2) COAXIAL CABLE

*Consists of wire surrounded by the insulation layer, shielding layer and an outer jacket.
*Quarter inch or more in diameter, therefore less flexible than twisted pair.
*Less susceptible to noise but more expensive than twisted pair.
* Wider bandwidth, more difficult to install/tap, more costly than twisted pair.
*Data rate up to 150 Mbps.
*Usage
- DATA COMMUNICATION
-VIDEO TRANSMISSION
-VOICE COMMUNICATION
*Used extensively in LAN and relatively Short distance (10 miles).
For longer distance, repeaters may be necessary.

(3) Fibre OPTIC CABLE :

One or more glass or plastic fibres are woven together to form the core of the cable. This core is surrounded by a glass or plastic layer called the cladding, which in turn is covered with plastic or other material for protection.
The light source used is either LASER or light-emitting diodes (L E D) Whereas detector is a photodiode.
*Low error rate, very high noise immunity, immunity to electrical and magnetic noise.
*Reduced size and weight(than copper or coaxial), but easy to break.
*High cost of installation with special equipment and skill required.
*Very expensive but may be economical for high-volume application
*Broad bandwidth.
*High data rate over 2 Gbps possible.
*Usage
-VOICE COMMUNICATION
-VIDEO COMMUNICATION
DATA COMMUNICATION
* Network using fibre optic are called "Fibre Distributed Data interface" FDDI) often ring based