Duplex (telecommunications)

Duplex (telecommunications)

A duplex communication system is a point-to-point system composed of two connected parties or devices that can communicate with one another in both directions simultaneously. An example of a duplex device is a telephone. The people at both ends of a telephone call can speak at the same time, the earphone can reproduce the speech of the other person as the microphone transmits the speech of the local person, because there is a two-way communication channel between them.

Duplex systems are employed in many communications networks, either to allow for a communication "two-way street" between two connected parties or to provide a "reverse path" for the monitoring and remote adjustment of equipment in the field.

Systems that do not need the duplex capability use instead simplex communication in which one device transmits and the others just "listen". Examples are broadcast radio and television, garage door openers, baby monitors, wireless microphones, radio controlled models, surveillance cameras, and missile telemetry