Method and apparatus for operating on companded pcm voice data

A method and apparatus for digitizing audio signals being generated from a plurality of parties (A,B) in order to provide audio communication between the parties with a minimum of interference. Each of the parties has an audio transmitter and receiver (38,58). The audio signals are converted (42) to a PCM companded signal for transmission to a rmote location, and there converted (46) to an eight-bit parallel signal. A preprogrammed ROM (48) is located at the remote location and has a plurality of inputs and outputs. Each of the eight-bit parallel signals from the individual parties are fed to the ROM which produces an eight-bit output signal representing the instantaneous sum of the eight-bit parallel signals being supplied to its inputs. The ROM output is converted to a serial-digital signal by a parallel-to-serial converter (50) for transmission over a single line (52) to another serial-to-parallel converter (54) prior to being fed through a DAC to the receiver (58).