## Transmission protocols

### Simplex #### A simplex communications link is defined as one where the communication flow can only occur in one direction. A common example is broadcast radio or television. ### Half duplex #### A half-duplex communication link is capable of communication in both directions, but not at the same time. This form of communication is commonly employed in applications from 'walkie-talkies' and CB-radio, through to professional police radio systems. ### Full duplex #### A full-duplex system, as one would expect, can support simultaneous two-way communication. The most widespread example is the telephone. |