The Control of Sectionalized Space-Division Switching Systems

The sectionalized system under consideration employs overall route choice techniques, in which the identity of lines to be connected is indicated in coded form, and free paths are selected in common equipment. Flexibility, high operating speed, and good security against faults are prime requirements of the common equipment in large exchanges. Initially, duplicated controls, based on capacitor stores and wired logic, are provided with automatic change-over, in the event of a failure. Current development is based on sectionalized controls, in which any of a number of stored program control units can set up each call.