A single chip S-interface transceiver for public and private ISDN

A single-chip S-interface transceiver has been realized for use in integrated services digital network (ISDN) public and private loops. It performs the physical-layer functions for interfacing voice and data communication equipment to the four-wire CCITT S-bus. The 22-pin chip is implemented in a 1.5-μm CMOS technology and can be configured to operate in terminal equipment in network termination applications or as a PABX line card device