Full Duplex transmission indicates the transmission of data in two directions simultaneously. For example, on a local area network with full-duplex transmission, one workstation can be sending data on the line while another workstation is receiving data. On the other hand, a half duplex transmission indicates that data transmission happens only in one direction at a time.

The most common example of a full-duplex network is the telephone system. Both parties can speak simultaneously during a telephone call and each party can also hear the other at the same time. An example of a half-duplex communication system is a two-way radio like a CB radio, in which only one party can transmit at any one time, and each party must say "over" to signal that he or she has finished talking.

With the right equipment, full-duplex communication is possible on certain types of LANs. The first requirement is a separate channel for traffic running in each direction. Whether this is possible depends on the network medium. Coaxial cable, for example, contains a single conductor and a ground, so there is no physical way that traffic could run in both directions, unless you were to install two cable runs for each connection. Twisted pair cable, on the other hand, contains four separate wire pairs within a single sheath, one of which is dedicated to incoming traffic and one to outgoing. Networks that use this type of cable can therefore theoretically operate in full-duplex mode, and some manufacturers are making Ethernet equipment that makes this possible. Full-duplex Ethernet essentially doubles the throughput of the existing network.

Full Duplex Transmission

Related Terms: Half Duplex