Abstract: The availability and location of a multiplicity of multiplexed digital information streams, transmitted over one of a multiplicity of channels, are identified by transmitting a Global Channel Map which includes a version number, one Band Map Table, one Channel Map Table, and at least as many Service Map tables as there are combinations of identical service types transmitted over different channels. The Band Map Table preferably contains an entry for each frequency band used by the system, and a Band Map Table version number. A Global Channel Map Updates file is transmitted in each band. Where a plurality of channels contain similar-types of services, one Service Map Table contains relative service identification numbers for those service types. The entries for relevant channels in the Channel Map Table contain base service identification data which are combined with the relative service identification number to locate a particular service transmitted over that channel.