Integrated circuits for ISDN-status and future

In 1985 Siemens Semiconductors introduced the first integrated circuits for ISDN based on the ISDN Oriented Modular (IOM) architecture and linked over the IOM interface. Now, four years later, they are introducing their second generation ISDN devices, thus enhancing the IOM architecture by a whole range of configurations. This has been made possible by the definition of the IOM-2 interface. The IOM-2 interface was defined as the General Circuit Interface (GCI) by the Group-of-Four, a cooperation of the telecom companies Alcatel, Italtel, Plessey, and Siemens. The paper describes the different stages of evolution of ISDN chips