This is a way of communicating on the half-duplex communication line, includes receiving and transmitting devices (walkie-talkie) by the way of pressing the button for switching to the voice mode or transition to the listening mode. It works as a radio speaker; one can talk by pressing the button and can listen to a voice message by releasing the button.
Offers connections ranging from capability for a couple of simultaneous calls for small PBX-equipped businesses to an unlimited number of channels for larger businesses.