A family (DP521/DP522/DP523/DP524) of 2-channel codecs used for point-to-point and point-to-multipoint signal distribution: ISDN, Switched-56, T1 or DS-3 networks; recording/post-production studio interconnection with or without video; and voice-over and other applications. AC-2 and AC-3 perceptual coding algorithms are supported to provide audio transfers at a total data rate between 56 kBps and 384 kBps. With AC-3, single-channel, two-channel, and composite stereo algorithms are supported.