Guided media are more commonly known as wired media, or those media in which electrical or optical signals are transmitted through a cables or wires. Unguided media are more commonly known as wireless media, in which electromagnetic signals are sent through space with no direction. Both types of media can be used for long-distance and short-distance communication.
In guided media, electrical signals are confined within the cable or wire which transmits them. Typical forms of guided media include copper co-axial cables, fiber-optic cables and twisted-pair copper cables, which can be shielded or unshielded. Guided media are also sometimes known as bounded media.
Different types of unguided, or wireless, communication are classified based on the frequency spectrum used for communication, the distance between the end stations and the type of encoding used for the communication. Unguided communication allows electromagnetic signals to travel between antennas, some of which are on satellites. Antennas can provide point-to-point communication or can send their signals in all directions.
Transmission of digital data through either guided or unguided communication involves the coding of the data at the sender's end, the modulation of the carrier signal, the demodulation of the signal on the receiving end and the decoding of the binary signal.