Consumer telephone III: Mixing new with old: An interfacing scheme for analog and digital systems features modular architecture

A telephone switching system that embodies a unique design philosophy is now into its third year of service. The AXE-10, a digital stored-program-control (SPC) system, is made up of functional modules in individual hardware and software configurations (Fig. 1). They are interconnected via strictly defined hardware and software interfaces. This building block principle makes the system generally applicable on all levels of the telephone network and permits smooth introduction of new parts into the system without changing its concept. Also, handling and operation of the system are easier as compared to the monolithic-type systems of earlier generation.