Two Way Radio

Two-way radio is a radio that can both transmit and receive a signal (a transceiver), unlike a broadcast receiver which only receives content. It is an audio (sound) transceiver designed for bidirectional person-to-person voice communication with other users with similar radios using the same radio frequency (channel). Two-way radios are available in mobile, stationary base and hand-held portable configurations. Hand-held two-way radios are often called walkie-talkies, handie-talkies or hand-helds.

Two-way radio systems usually operate in a half-duplex mode; that is, the operator can talk, or he can listen, but not at the same time. A push-to-talk or Press To Transmit button activates the transmitter; when it is released the receiver is active. Other Full-duplex is generally achieved by the use of two different frequencies or by frequency-sharing methods to carry the two directions of the conversation simultaneously. Methods for mitigating the self interference caused by simultaneous transmission and reception on different but close-spaced frequencies include using two antennas, or dynamic solid-state filters. Time-division technologies (such as TDD) are used for mitigating self interference by simultaneous transmission and reception on the same frequency.