Half-Duplex
Half-Duplex is a term used in data transmission systems where data can be transmitted in both directions on a signal carrier, but not at the same time. In half-duplex system only one party can transmit data at a time.
In a half-duplex system, once a party start receiving data, it must wait for the transmitter to stop transmitting, before replying. An example of a half-duplex system is a two-party system such as a "walkie-talkie" style two-way radio. A LAN which uses half-duplex transmission, one workstation can send data on the line and then immediately receive data on the line from the same direction in which data was just transmitted.