Developments in selective calling systems

This paper describes three monolithic encoder/ decoder integrated circuits for 5-tone mobile selective calling systems operating to European CCIR and ZVEI standards. Methods for code programming group calling and conditioned transponding are discussed. A new series of codec integrated circuits are also described, to be available in versions pre-programmed to the American EIA frequencies. These integrated circuits provide selective address, group call, all-call, ATI, status transponding and two way data signalling capabilities for fully integrated mobile-portable-paging communications systems.