Theory - 65 :- Transmission Medium in Computer Networks

What is Transmission Medium in Computer 

Networks?

A transmission medium in computer networks is a communication channel between sender and receiver and it is used to transfer data from one network to another. 

When two or more computers are interconnected through a medium to exchange messages or information, then the medium is known as a transmission medium in computer networks. The transmission medium is also called transmission media.

The transmission medium is a media between interconnected devices. Different types of transmission media have unique properties and are used for different purposes.

Types of Transmission Medium

In computer networks, we mainly classify the transmission medium into two types, such as guided and unguided media. The following diagram shows the broad classification of the transmission medium in computer networks.

What is Guided Media?

The media which has a point to point physical connection is called guided media. It is a communication medium that allows data to get guided along with it. 

Guided media is also called wired or bounded media. Different types of wires are used to make a physical connection between devices. 

Types of Guided Media

Guided media is mainly classified into three types:

• Twisted pair cable,
• Co-axial cable
• Optical fibre.
• Twisted Pair Cable

The two wires are typically twisted together in a helix to reduce interference between the two conductors. Twisted pair cables can carry both analog and digital signals. There are two types of twisted pair cables as follows.

UTP (Unshielded Twisted Pair Cable)

A twisted pair in which two insulated conductors are twisted together is called an unshielded twisted pair cable. UTP cable is very cheap and easy to install.

STP(Shielded Twisted Pair Cable)

It has a metal foil or mesh to cover each pair of insulating conductors. This is also known as the metal shield. The following are the application of an STP cable.

• In telephone lines to carry voice and data channels.
• In the local loop.
• In DSL line.

Co-axial Cable

It comprises two conductors that are separated by a dielectric material. The external conductor is a metallic braid and is used for the purpose of shielding. There are three categories of a co-axial cable, such as RG-11, RG-58 and RG- 59. 

The following are the applications of a co-axial cable.

• Analog telephone networks.
• Digital telephone networks.
• Cable TV.
• Digital Transmission.

Optical Fiber Cables

It comprises an inner glass core surrounded by a glass cladding. The cost of fibre optic cable is higher than the twisted pair and co-axial cable. These cables are small and have lightweight. The installation of fibre optical cable is difficult. 

The following are the applications of optical fibre cable.

• In the local area networks (LANs).
• Optical fibres are now used in telephone systems.
• These are used in the backbone of networks.