No. 1 EAX Common Control

This paper describes the common control subsystem of the No. 1 electronic automatic exchange (EAX) switch. The data-processing unit is a high-speed interrupt-driven general-purpose computer. It is broken down into its component parts of control, memories, communication channels, and input/output and its functions are described. The register-sender, a hard-wired preprocessor that handles both incoming and outgoing signaling for the switch is described, together with its relationship with the space-divided junctor circuits. The level of redundancy and its effect on the system structure and organization are described and discussed.