Computer Notes: Transmission Media and Its Types

Transmission Media and Its Types - Banking Notes

Introduction:
The communication in a network is only possible if the information is coded into a signal and is transferred through a transmission medium. The transmission medium acts as the medium or physical path between the transmitter and the receiver in the data transmission system. 

Characteristics of the Media:

• It provides good quality communication at long distance.
• It ensures higher data rate at long communication distance at a lower cost.
• There are 3 factors which affect the maximum communication distance and maximum data rate of a medium. These factors are interference, communication bandwidth of medium and the transmission impairments.
• The interference is the distortion on signal in the transmission due to the unwanted signals from the outside sources.
• The bandwidth of the medium determines the signal frequencies.
• The transmission impairments include noises, distortion during the signal propagation.

Classification of Transmission Media:
The transmission media is classified into two major categories i.e. Guided Transmission Media and Unguided Transmission Media.
Guided Transmission Media:

• It constrains and guides the communication signal.
• The Signals are transmitted through the physical and tangible guide between communicating points.
• It includes Fiber Optics cable, Twisted Pair Telephone cable, wave guide and coaxial cable.

Types of Guided Transmission Media:
Twisted Pair Cable-

• The pairs of wires are twisted around to make this type of cable.
• The wires are twisted together to reduce the crosstalk and noise susceptibility.
• This type of cable is of 2 types i.e. UTP and STP.
• STP (Shielded Twisted Pair) is covered with the foil shield to reduce interference and cross talk between the pair of wires. It is bulky and difficult to use.
• UTP (Unshielded Twisted Pair) does not have any extra shield around the pairs of wires. It is cheap and easy to install.  
• Applications- Telephone line, ISDN etc.

Coaxial Cable-

• It is a copper cable which is mostly used by the Cable TV companies for distributing TV signals.
• It is also known as Coax.
• It carries the signal of higher frequencies. 
• Applications- Cable TV, Local Area Networking, Long Distance Telephone Transmission etc.

Fiber Optics Cable-

• This kind of cable uses the light to send the information.
• It provides high bandwidth for voice, video and applications of data.
• It is more reliable and secure.
• It can carry larger information than the other wires.
• The information loss is very less in this kind of cable.

Unguided Transmission Media:

• It permits the signal to be transmitted but never guide them.
• There is no direct physical connection between the two points i.e. satellite links and microwave.
• The examples of Unguided Transmission Media are radio signals, microwave, Satellite signal and infrared.

Types of Unguided Transmission Media:
Satellite Communication-

• The artificial satellite is man made.
• It consists of a radio transmitter and transponder.
• It provides communication over longer distance than others.
• It is used in video conferencing, GPS (Global Positioning System) etc.

Microwave Communication:

• The microwave is a kind of electromagnetic waves.
• It is used when the physical transmission media cannot be installed under any circumstances (mountains, jungles, rivers etc).
• The microwave transmission is the line of sight transmission.

Radio Communication:

• It is used for wireless communication.
• Applications-  Portable phones, Sending/Receiving Computer data.

Infrared Communication:

• The infrared technology allows the devices to communicate via short range wireless signals.