COMMUNICATIION MEDIA
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It is a pathway that is used form transferring
data from sender to receiver.
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These paths are called communication channels
GUIDED MEDIA
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It refers to communication channels that allow
the transmission of data through a physical media
·
These are also called bounded media
·
Examples are twisted pair , coaxial and Fiber
Optic
TWISTED PAIR
·
These are used in local communication and short
distance digital transmission
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It is made of copper and pair of wires are
twisted together to reduce the interference by adjacent wires
·
These are used to connect terminals to the main
computer place at a very short distance
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Data transmission speed is up to 9600 bps if the
distance is not more than 100 meters
·
It is an expensive medium for transmission
·
It is easy to install
·
Its bandwidth is less than coaxial and fiber
optic cable
CO AXIAL;
ADVANTAGES;
·
It can be used for long distance telephone lines
for data and voice transmission at a very high frequency
·
The bandwidth of coaxial cable is 80 times greater
than twisted pair media
·
It is also used in LAN
·
It has a low transmission error rate i.e. it
creates less distortion or less interface of electromagnetic waves
STRUCTURE;
·
It consists of copper wire surrounded by
insulating material.
·
It contains 4 to 22 coaxial units called tubes.
·
Each coaxial unit consists of 1.0 inch copper
inner conductor kept centered within 0.375 inch cylindrical copper outer
conductor by polythene insulating disks spaced about 1 inch apart.
FIBRE OPTIC:
STRUCTURE:
·
Fiber optic cable consists of tubes of glass
through which data is transmitted as pulse of light.
·
A normal fiber optic is fibre of glass called
the core . The diameter of core is 62.5 micron
·
The core is surrounded by concentric layers of
glass called the cladding . The diameter of cladding is 125 micvron.
·
The cladding is surrounded by a plastic layer called
jacket
CHARACTERISTIC
OF FIBRE OPTIC :
·
Refraction is the characteristic of fibre optic
i.e either pass or rreflect the light.
·
When lght passes through a medium , it bensd as
it passes from one medium to another
ADVANTAGES :
·
ITS TRANSMISSSION IS VERY FAST
·
It is not affected by electromagnetism
interference
·
Its error rate is low
UNGUIDED MEDIA ;
The type of Communication media in which communication devices sends and receives data signals through air or space is called Unguided media. The data is communicated in the form of wave. Unguided media provides means to transmit data signals but does not guide them along a specific path. The data signals are not bounded to a cabling media. Therefore, unguided media is also called Unbounded media.
This transmission medium is used when it is impossible to install the cables.The data can be transmitted all over the world through this medium. The examples of unguided media are:
The data is transmitted and received through a microwave station. A microwave station is also called relay station or booster. A microwave station contains an antenna, transmitter, receiver, and other equipments that are required for microwave transmission. Microwave antennas are placed on the high towers or buildings. These are placed within 20 to 30 miles of each other. there may be many microwave stations between the sender and receiver. data is transmitted from one microwave station to another. Each microwave station receives signals from previous microwave station and transmits to next station. In this way, data is transmitted over larger distances.
2- Satellite Communication
Satellite communication system consists of a satellite and several earth stations. The communication satellite is a space station. It is approximately 22,300 miles above the earth. Each earth station consists of large dish antenna. It can send and receive data signals.
A satellite receives microwave signals (or messages) from earth station. It amplifies the signals and sends them to another earth station. In this way, data is transferred from one location to another. Data transmission speed of satellite is very fast.
Advantage: The main advantage of satellite communication system is that a large amount of data can be communicated from one country to another.
Disadvantage: The disadvantage of satellite communication is that bad weather can affect the quality of satellite transmission.
3- Mobile Communication
Mobile communication is a radio-based network. It sends and receives data to and from the mobile computers. The data is communicated through radio signals from one location to another. The Computers can be connected to the network through wireless connections or through wires.
UNGUIDED MEDIA ;
The type of Communication media in which communication devices sends and receives data signals through air or space is called Unguided media. The data is communicated in the form of wave. Unguided media provides means to transmit data signals but does not guide them along a specific path. The data signals are not bounded to a cabling media. Therefore, unguided media is also called Unbounded media.
This transmission medium is used when it is impossible to install the cables.The data can be transmitted all over the world through this medium. The examples of unguided media are:
- Microwave
- Satellite Communication
- Mobile Communication
The data is transmitted and received through a microwave station. A microwave station is also called relay station or booster. A microwave station contains an antenna, transmitter, receiver, and other equipments that are required for microwave transmission. Microwave antennas are placed on the high towers or buildings. These are placed within 20 to 30 miles of each other. there may be many microwave stations between the sender and receiver. data is transmitted from one microwave station to another. Each microwave station receives signals from previous microwave station and transmits to next station. In this way, data is transmitted over larger distances.
2- Satellite Communication
Satellite communication system consists of a satellite and several earth stations. The communication satellite is a space station. It is approximately 22,300 miles above the earth. Each earth station consists of large dish antenna. It can send and receive data signals.
A satellite receives microwave signals (or messages) from earth station. It amplifies the signals and sends them to another earth station. In this way, data is transferred from one location to another. Data transmission speed of satellite is very fast.
Advantage: The main advantage of satellite communication system is that a large amount of data can be communicated from one country to another.
Disadvantage: The disadvantage of satellite communication is that bad weather can affect the quality of satellite transmission.
3- Mobile Communication
Mobile communication is a radio-based network. It sends and receives data to and from the mobile computers. The data is communicated through radio signals from one location to another. The Computers can be connected to the network through wireless connections or through wires.
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