Abstract: A portable radio telephone handset operates as a data transfer terminal as well as an analog cellular telephone subscriber station. Two modes of operation, an analog cellular communication mode and a Cellular Digital Packet Data (CDPD) mode, are available in the handset. The handset distinguishes between paging signals indicating CDPD mode communications and those indicating analog cellular communications. The handset also automatically preempts CDPD communications in favor of analog cellular communications such as those carried out in an AMPS configuration. The handset maintains an active status on a CDPD communication channel during a “sleep mode”, when the handset can carry out AMPS activity.