Abstract: The system requires the use of the permanent ID of the requesting unit in every channel request made on a control channel before every transmission. The channel grant will include the ID along with the channel number and these may be recorded for possible later reference. A channel assignment is retained for a brief period after each transmission, allowing a conversation to be continued on the same channel without a break. Units can access the control channel with a channel request and be assigned a channel even while the dispatcher is using the voice channel. In the case of a need for communication with a larger group, a dispatcher can form a temporary "patch" group of all involved units, with a temporary ID assigned to that group. A channel request from a member of the larger group must then include, not only the permanent ID of the requesting unit, but the temporary ID of the "patch" group.