Transmission media is the material pathway that connects computers, different kinds of devices and people on a network. It can be compared to a superhighway carrying lots of information. Transmission media uses cables or electromagnetic signals to transmit data.
There are two types of transmission media used in communications. The first type is called bound transmission media or guided media. It uses physical links, such as coaxial or fiber optic cables, to transmit data to the desired connection. Most cables are made of copper and bound by some form of jacket material. Because they are tangible, this type of media is limited to a fixed location.
The second type is unbounded media, also known as unguided or wireless media. Unlike bound media, it transmits data without any physical connectors between two communicating devices. Instead, it uses microwave, infrared or radio signals to transmit information.