Transmission Medium and Its Types

Communication or Transmission medium
Transmission medium is a channel through which data or signals can be transmitted from one point to another.

Different types of cables or waves are used to transmit data.

There are two types of transmission medium. They are guided medium and unguided medium

The differences between bounded media and unbounded media

Bounded media	Unbounded media
Bounded media are the physical links through which signals are confined to narrow paths.	Unbounded media are wireless media that do not use any physical connections between the two communicating devices.
It travels in a contained conductor.	It uses a transmission carrier to send data signals through the air instead of cables.
e.g.: coaxial cable, twisted pair cable and fiber optics cable.	e.g.: radio waves, micro waves and infrared waves.

Twisted pair cable

A pair of wires which are made of copper and are twisted with each other is known as twisted pair cable.

A set of four pairs of twisted wires are bundled to form cable.

Wires are twisted with each other so as to reduce the interference.

The types of twisted pair cable are Unshielded Twisted Pair Cable and Twisted Pair Cable

The differences between shielded twisted pair and unshielded twisted pair are:

Shielded twisted pair	Unshielded twisted pair
It is made up of twisted pair wires with additional shielded and drain wires to drain away noioses.	It is made up of twisted pair wires without additional shielded and drain wires.
It covers shorter distance and has better noise rejection capacity.	It covers maximum distance of 100 metres
It is costlier than UTP cables	It is cheaper than STP cables
D-shell connectors are used with shielded twisted pair.	Cat 5 cable with RJ-45 connector is commonly used with unshielded twisted pair.

Co-axial cable

A cable which is used with single ended single reference where the central conductor carries the data signal is called co-axial cable.

The connectors used with co-axial cables are BNC, T-connectors and terminators in bus topology.

10 Mbps is the maximum speed of co-axial cable.

Fiber optics cable

Fiber optics cable is one of the costlier cables used in data communication which uses light to carry a data signal through the cable.

The connectors used in fiber optics are Screw Mounted Adaptors (SMA), Spring-loaded Twist (ST), SC and FC.

It is costlier to maintain, produce and install.          

The advantages of radio wave transmission.

It offers mobility.

It offers ease of communication over different terrain.

It offers freedom from land acquisition rights that are required for laying repairing cables.

It provides cheaper than digging trenches for laying cables and maintaining repeaters and cables if cables get broken by a variety of causes.

The advantages and disadvantages of microwave transmission

Advantages

They have the ability to communicate over oceans.

It offers ease of communication over difficult terrain.

Disadvantages

It is an insecure communication.

It is susceptible to weather effects like rain, thunder storms etc.

The differences between radio wave and microwave are as follows:

Radio wave	Microwave
It is a form of wireless communications in which signals are sent through radio frequency waves.	It is a form of wireless communication in which data signals are sent through pulses of electromagnetic energy.
It provides low bandwidth for data communication.	It provides higher bandwidth for data communication.
It does not require line of sight for data transmission	It requires line of sight for data transmission.

Infrared transmission

Infrared transmissions are just below visible transmission light which allows high speed data transmission.