INTRODUCTION OF ISDN SOFTWARE IN EXISTING DIGITAL TELEPHONE EXCHANGES IN AN EVOLUTIONARY WAY

摘要

The task of realizing an ISDN based on digital switching centers operating within the conventional telephone network presents a real challenge in terms of the system concept and software development technology.The novelty of the ISDN features on the one hand and the unavoidable links to existing functions on the other call for a very careful analysis of the functional structure.Beyond that one must consider system criteria such as dynamics,statics,ease of maintenance,stability and,above all,future expandability.The evolutionary approach to accommodating ISDN functions in the SIEMENS SYSTEM EWSD consists in packaging the software,even in those software complexes which display the highest degree of interdependence.