Abstract: A method and system for radio communications between mobile units and base stations geographically distributed through a substantial geographic area described. The system automatically finds and engages broadcast frequency for each geographic region. The engagement is confirmed at both the mobile unit and network so that both can begin data transmission and reception between each other as well as keep track of the status of one another. The system also verifies the correct base station has been engaged as well as automatically terminates communications once the mobile unit passes out of coverage for that base station.