Stored Program Controlled Network: No. 1/1A ESS-SPC network capabilities and signaling architecture

The No. 1/1A Electronic Switching System (ESS) will play an important role in the evolving Stored Program Controlled (SPC) Network because, as a major electronic switching system for local and combined local/toll service, it provides direct interfaces to many of the Bell System's customers. It provides important capabilities required for System 800 Service and for a variety of other new SPC network services. This paper describes several of the basic SPC network capabilities provided by the No. 1/1A ESS. It also describes the architecture and implementation of its common-channel interoffice signaling (CCIS) subsystem, CCIS call-processing software, and System 800 software.