Trunked radio repeater system

A digitally trunked radio repeater system provides substantial improvements in timeliness of channel acquisition and channel drop, and in reliability of critical control signaling. The system uses a control channel to convey digital channel request and assignment messages between the central site and mobile transceivers. The mobile radio transceivers transmit channel requests on the control channel and switch to a working channel in response to an assignment message received on the control channel. Subaudible digital signals transmitted on the active working channels allow late entry, shifting to higher priority calls, and other advanced functions and high-speed data bursts may be included at a predetermined time within a subaudible digital signal frame. The receiver audio circuitry is muted during reception of such bursts.