Radio telecommunication network and method for unobtrusive call interception via transcoder bypass

摘要

A digital cellular telecommunication net-work (30 ) uses transcoders (50) which vocode voice using a maximal lossy compression algo-rithm which conserves Spectrum usage. A call path for an intercepted call is looped from an outer space satellite (32) network into an inter-cepting terrestrial gateway (34). Compressed call data for each of two half-calls in this call path by-pass normal transcoders (50) through the use of rate adapters of an earth terminal controller (54) which translate between data communication protocols that operate at different data rates without voice coding and decoding After rate adaption, the compressed call data are combined in a confer-ence bridge of a mobile switching center (56), 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.