Training for the no. 1 ESS

Abstract

The first installation of the No. 1 Electronic Switching System (No. 1 ESS), a stored-program electronic telephone switching system developed by Bell Telephone Laboratories, started commercial operation in Succasunna, New Jersey, on May 30, 1965. In the No. 1 ESS, call processing and maintenance functions are performend under the control of a program of some 100,000 words stored in a readonly type of memory. The 44-bit instructions are executed by a central processor operating on a basic cycle time of 5.5 microseconds. A read-write type of memory with 24-bit word locations is used for the storage of transient information such as the digits dialed by a subscriber.