PCM channel multiplexer/demultiplexer

Claim 1

Apparatus for multiplexing N number of sample frame signals received at a frame bit rate from N number of station devices of a communications system having a source of timing signals, each frame signal including pulse code modulated (PCM) samples of signal port voice, data, and control signal bits in an interleaved port group format, into a time slot interchange (TSI) PCM sample signal with voice, data, and control signal bits grouped in signal bit units of common signal type for presentation to the system TSI matrix at an N times greater frame bit rate, and for demultiplexing return TSI PCM signal samples into port grouped PCM signal samples for return to the station devices, the apparatus comprising: memory means for storing signals; station interface means, responsive to the sample frame signals at a station interface input and at a station interface output thereof, said station interface input storing the port grouped voice, data, and control signal bits received from each station device in a station portion of said memory means, said station interface output retrieving, in a first retrieval sequence, common signal type bit units of each return TSI PCM sample signal stored in a TSI portion of said memory to provide the interleaved port group format of voice, data, and control signal bits for return to each station device; and TSI I/O means, responsive to the TSI PCM signal at a TSI interface input and at a TSI interface output, said TSI interface input storing each return TSI PCM sample signal from the TSI matrix in signal bit units of common signal type in said TSI portion of said memory means, said TSI interface output retrieving, in a second retrieval sequence, said interleaved port groups of voice, data, and control signal bits stored in said station portion of said memory to provide the TSI PCM signal bit units of common signal type for presentation to the TSI matrix.