half duplex

communications which can transfer information in only one direction at a time

A duplex communication system is a system composed of two connected parties or devices which can communicate with one another in both directions. (The term duplex is not used when describing communication between more than two parties or devices.)Duplex systems are employed in nearly all 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.
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<communications> (hdx, from telegraphy) 1. A type of communication channel using a single circuit which can carry data in either direction but not both directions at once.
Compare: simplex, full-duplex.
2. An obsolete term for local echo.
(2001-07-21)