Communication Channels | Guided And Unguided


Hey geeks, welcome back to Techatronic. Do you know what a communication channel or medium is? Well, if not then in this article we are going to talk about communication channels and their types. The medium on which the information is passed from the transmitter to the receiver is called a communication channel. Depending on the mode of transmission, we may classify them into two categories mainly. You can read articles on basic electronics and Arduino.

First of all, let us see the types of communication channels for guided communication.

Twisted Pair Cables

communication channels
  • Telephone channels can be twisted pair cables or shielded twisted pair cables.
  • They are made from a pair of copper wires.
  • This method is suitable for sharing the data or information at short distances only and is also called LAN (local area network).

Coaxial Cables Communication channels

communication channels
  • It consists of two concentric conductors separated by a dielectric material.
  • This medium for communication has a good noise immunity with low losses.
  • In coaxial cables, we need to use repeaters after covering 1 KM of distance.
  • These cables are also used for LAN.

Optical Fiber

communication channels
  • It consists of an inner glass core surrounded by glass cladding which has a lower refractive index.
  • Digital signals are transmitted in the form of intensity (modulated light signal which is trapped in the glass core).
  • The working principle of an optical fiber is TIR (total internal reflection).
  • Light is launched into the fiber using a light source such as LED or laser, it is deflected on the other side using a photodetector such as a photo transistor.

Now let us talk about unguided channels for communication.


  • This communication channel is used for the transmission of TV and radio signals.
  • The modulated signal is transmitted in all possible directions from transmitter. Normally EM (electromagnetic) waves are transmitted as either sky waves, space waves, or ground waves.
  • Certain antennas mounted on the hall or tower acts as repeaters.
  • At receiving end receiving antenna is used to pick signals.

Radio Channel

communication channels
  • The radio wave propagation takes place due to the scattering of EM waves from the surface of buildings and diffraction over & around them.
  • Hence the transmitted signal reaches its destination following different paths of different lengths.
  • This is called multipath communication.
  • The total strength of the signal at the receiver is equal to the vector sum of all signals.


We hope that you understand the need and types of communication channels completely. If you have any doubts regarding this post then do let us know in the comments section given below. Also, do check out more articles on Arduino and Raspberry Pi.

Happy Learning!

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