What are the types of Transmission media?

Signals are usually transmitted over some transmission media that are broadly divided in to two categories:-

Guided Media:

These are those that give a conduit from one device to another that contain twisted-pair, coaxial cable and fiber-optic cable. A signal travelling along any of these media is directed and is restricted by the physical limits of the medium. Twisted-pair and coaxial cable use metallic that accept and transport signals in the form of electrical current. Optical fiber is a glass or plastic cable that contains and transports signals in the form of light.

Unguided Media:

This is the wireless media that transport electromagnetic waves without using a physical conductor. Signals are broadcast either by air. This is done by radio communication, satellite communication and cellular telephony.