A two-way radio may be a radio which will both transmit and receive radio waves (a transceiver), unlike a broadcast receiver which only receives content. it’s an audio (sound) transceiver, a transmitter and receiver in one unit, used for bidirectional person-to-person speech with other users with similar radios. Two-way radios are available in stationary (base station), mobile (installed in vehicles), and hand-held portable models. Hand-held two-way radios are often called walkie-talkies, handie-talkies or hand-helds. Two-way radios are employed by groups of geographically separated people that got to confine continuous speech , like aircraft pilots and traffic controllers, ship captains and harbormasters, emergency services personnel like firemen, policemen, and ambulance paramedics, taxi and delivery services, soldiers and military units, nutriment and warehouse employees, and radio amateurs.
Two-way radio systems usually use one radio channel and operate during a half-duplex mode: just one user on the channel can transmit at a time, so users during a user group must alternate talking. The radio is generally in receive mode therefore the user can hear all other transmissions on the channel. When the user wants to speak he presses a “push-to-talk” button, which turns off the receiver and activates the transmitter; when he releases the button the receiver is activated again. Multiple channels are provided so separate user groups can communicate within the same area without interfering with one another . Other two-way radio systems operate in full-duplex mode, during which both parties can talk simultaneously. this needs either two separate radio channels or channel sharing methods like time division duplex (TDD) to hold the 2 directions of the conversation simultaneously on one frequency . A telephone is an example of a full-duplex two-way radio. During a call , the phone communicates with the cell tower over two radio channels; an incoming one to hold the remote party’s voice to the user, and an outgoing one to hold the user’s voice to the remote party.