Introduction to Networking

Transmission Media

Transmission media is the part of the physical layer which provides a path through which data is transmitted from one place to another. It is also known as a transmission channel, Communication media, or communication channel.


  • The amount of data that can be transferred through a communication medium in a unit of time is called bandwidth.
  • The bandwidth of the digital signal is measured in bits per second or bytes per second.
  • The bandwidth of Analog’s signal is measured in cycles per second or Hertz.

Types of Transmission Media

There are two major types of Transmission Media. One is Physical medical, and the other is wireless.

Physical transmission media is known as Guided Transmission Media, and Wireless transmission media is known as Unguided Transmission Media. A descriptive diagram of transmission media is given below.

In upcoming lectures, we will see the types of transmission media in detail.

Transmission Impairment 

There are three major types of transmission impairment, explained under

  • Attenuation: The strength of the signal decreases when the distance increases, which causes the loss of energy.
  • Distortion: Distortion occurs when there is a change in the shape of the signal. Changing the shape of the signal means the signal changes its amplitude.
  • Noise: When data is travelled over a communication medium, some unwanted signals may added to it, which creates noise.