A duplex communication system is a point - to - point system composed of two or more connected parties or devices that can communicate with one another in both directions. 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. There are two types of duplex communication systems: full - duplex (FDX) and half - duplex (HDX).
in which mode the communication channel is used in both directions at the same time
A duplex