Abstract: A digital cellular telecommunication network (30) uses transcoders (50) which vocode voice using a maximal lossy compression algorithm which conserves spectrum usage. A call path for an intercepted call is looped from an outer space satellite (32) network into a terrestrial gateway (34). Compressed call data for each of two half-calls in this call path are duplicated at any of the network nodes and inserted into the opposing half-call. In addition, the compressed call data are decompressed in a gateway transcoder (50), combined in a conference bridge (90), and routed to a monitoring center (60). A subscriber unit (36), a second device (48), and the monitoring center (60) all receive call data which has experienced only one compression/decompression cycle.
Type:
Grant
Filed:
December 18, 1995
Date of Patent:
January 20, 1998
Assignee:
Motorola, Inc.
Inventors:
Peter Joseph Armbruster, Johanna Alexandra Wild, Dean Paul Vanden Heuvel, Scott David Blanchard