
channel processing in an ISDN exchange termination is very expensive using commercially available serial communications devices. This is because semiconductor manufacturers understand ISDN from the perspective of a terminal which is different from that of a network: the former sees one

channel, whereas the latter must deal with many. Consequently, commercially available devices are designed to support a small number of channels, whereas exchange terminations must cost-effectively support a large number of channels. This paper describes an innovative VLSI architecture that uses multiplexing to allow many channels to share serial communications circuitry as well as external message buffering. This capability will greatly reduce the hardware cost and complexity of

channel processing in ISDN exchange terminations.