A communication system of the type wherein a central station assigns a limited number of information channels to a requesting one of a plurality of remote stations is disclosed. The requesting station sends its identification signal along with the request signal to the central station on a signal channel. The central station classifies the requesting station in either a priority or a nonpriority queue. The priority queue corresponds to those stations which are continuing an on-going interchange, whereas the nonpriority queue contains those stations which wish to initiate an interchange. Stations are prioritized in the queues on a first-in/first-out basis.
The central station constantly monitors the information channels and, as channels become available, assigns the channels first to stations in the prioirty queue, then to nonpriority queue stations. A channel becomes "available" when the central station detects a pause, such as a momentary release of a push to talk microphone switch, in transmission on that channel. By this transmission trunking method, the system makes optimum use of the limited number of available channels.
Additional central station processing provides an acknowledgement signal, which indicates that the request was received and a channel will be assigned as soon as one becomes available. Also, the identification of a requesting station is compared with an associate memory. The memory provides the identifications of all stations to whom the requesting station would transmit. Once a channel is available, it is assigned to the requesting station and to its associated stations, whereby the associated stations are notified of, and prepared for, the impending transmission.