Abstract: An interface between mobile telecommunication stations and trunks that link with communication carriers of various media comprises station channels (11, 12, 13, and 14) that connect to telecommunication stations, trunk channels (1, 2, 3, and 4,) that connect to trunks that link to communication carriers, software code executable for interrogating the trunk channels for availability, software code executable for determining the communication medium or network of least cost, and software code executable for routing the telephone call from one of the station channels to the available trunk channel linked to the communication carrier having the medium or network of least cost. If the routing is to a trunk line linked to satellite communications, the interface selects the coast earth station of least cost based upon the location of the ocean going vessel, the destination of the call, and other rate considerations.