No. 10A Remote Switching System: Control-complex architecture and circuit design

The Remote Switching System (RSS) control complex contains the common circuitry needed to communicate with the host ESS and operate the other equipment in the RSS frame (switching network, line interface circuits, transmission channels, service circuits, etc.) as required to perform the functions of detecting originations, establishing and tearing down network connections, ringing telephones, and all of the other basic functions of a telephone switching system. In this capacity, the RSS control complex is analogous to the central control of a conventional ESS, rather than being a simple frame controller. This control complex contains two equivalent processors. One is active and the other is standing by to ensure reliability.