Abstract: A land mobile radio communication system has a plurality of cell cites, each of which includes a plurality of repeaters. The mobil radios in the cell transmit and receive both data and audio. The date component of the signal is carred as low-frequency subaudible information. In operation the system determines the number of repeaters that are available. When the system has determined that more than a predetermined number of the repeaters are available, all of the repeaters are set to repeat audio and to transmit and to receive data. However, when the system determines that only the predetermined number of repeaters are available, all of the repeaters, except for the ones of the repeaters in the predetermined number, are set to repeat audio and to transmit and receive data. The ones of the repeaters in the predetermined number are set to only transmit and receive data.

Abstract: A method and apparatus for placing calls in a multi-system land mobile radio network. A plurality of call destinations are linked or grouped together into a call group. Each call destination has a preferred system. Selection of a first call destination points to or is linked to at least a second call destination. If the preferred system for a current call destination is not accessible, then a second call destination, selected in accordance with the first call destination is made the current call destination. Selecting a call group causes a radio to attempt a plurality of call destinations, each in sequence, until an accessible preferred system is found, indicating that the current call destination is valid. If an accessible system is found, then the call is placed thereto.