Application of microprocessors to communication system

The use of a Microprocessor and PROM memories in an Electronic Loop Switching System has been described. The use provides telephone service for up to 128 subscriber lines using 32 trunks with increased reliability, maintenance capabilities, and flexibility. Date Communication between the central office terminal and the remote terminal is by FSK at 1-KHz rates over an idle trunk. Software functions and traffic handling capabilities are also described.