ISDN-Oriented Modular VLSI Chip Set for Central-Office and PABX Applications

Abstract

This paper describes a new ISDN-oriented modular (IOM®) architecture developed to establish the subscriber basic access to an Integrated Services Digital Network in a central-office or PABX environment with a minimum number of VLSI circuits. A four-component VLSI chip set is presented, consisting of the S-bus interface circuit (SBC), the ISDN burst transceiver circuit (IBC), and the ISDN echo cancellation circuit (IEC) for layer 1 data transmission at the fourwire <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">S</tex> and the two-wire <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">U</tex> interface, respectively, and the ISDN communication controller for layer 2 link access protocol control. The development strategy, the functions of the IC's, and examples for their application in the subscriber terminal and digital subscriber line board are emphasized.