Abstract: A moble radio system is disclosed in which communication is established between at least two user-operable stations over one of a plurality of channels by operating the user-operable stations in accordance with the following steps:(1) When in the receive mode (the push-to-talk switch is open):(i) incrementing the channel selector to select a channel;(ii) determining if a carrier signal is present on the selected channel:(iii) if a carrier signal is not present, returning to step (1) (i);(iv) if a carrier signal is present, determining if the selected trunk identification signal is present on the carrier signal;(v) if the selected trunk identification signal is not present, returning to step (1) (i); and(vi) if the selected trunk identification signal is present on the carrier signal, enabling said transmitter for push-to-talk operation.