A system for communicating with the user of a cellular telephone via the cellular mobile radio (CMR) system and the public switched telephone network (PSTN). A communications interface appends the telephone exchange number of an outgoing communication to include an identifier unique to the communications interface. The outgoing communication is transmitted by the cellular telephone to the CMR system, which recognizes and verifies the outgoing communication as originating with the communications interface. Accordingly, the origination of the outgoing communication from a communications interface is documented prior to forwarding the outgoing communication to its intended recipient via the PSTN. Communications incoming to a communications interface are authenticated as such, and a record as to this is created, prior to forwarding the incoming communication to the cellular telephone.