Define transmission media

Transmission media are the physical or wireless channels through which data signals travel from a sender to a receiver. They form the layer below the physical layer in the OSI model.

They are of two types:

• Guided (bounded) media: the signal follows a physical path, such as twisted pair, coaxial cable and optical fibre.
• Unguided (unbounded) media: the signal travels through air or space without a conductor, such as radio waves, microwaves and infrared.

The choice of medium depends on bandwidth, attenuation, cost, distance, installation, and noise immunity.