No. 1 ESS Call Store - A 0.2-Megabit Ferrite Sheet Memory

The central processor controls the operation of the No. 1 electronic switching system by executing sequences of program instructions. The logical organization of the central processor is described by the simultaneous evolution of: (1) an instruction repertoire to carry out the required telephone and system maintenance tasks efficiently, and (2) a circuit logic design to provide the necessary circuits (flip‐flop registers, accumulators, etc.) to execute the instructions at a high data processing rate. The design aims, order structure, timing, internal sequencing, and communications with the peripheral equipment of the system are described.

Organization of No. 1 ESS Central Processor

Harr¹,

Taylor²,

Ulrich³

1964

No. 1 ESS Bus System

Connell¹,

Hussey²,

Ketchledge³

1964

Communication between the various units within No. 1 ESS demands a complex network of transmission lines. The requirements are radically different from previous offices because a large amount of information must be transmitted at high speed, in digital form, between a multiplicity of locations with a high degree of reliability. A description is given of objectives and of organization and operational modes for the network. The problems involved are discussed together with the hardware by which the objectives were successfully realized.

No. 1 ESS Apparatus and Equipment

Ferguson¹,

Grutzner²,

Koehler³

et al. 1964

No. 1 ESS provides a greater variety of services than any prior complex switching system, in central offices of greater capacity, but with more highly standardized equipment of much smaller volume. Much of the credit for this achievement is due to the use of fast electronic circuits under control of a generic program. Apparatus and equipment development was aimed at accenting the benefits in this system, disciplining options to concentrate demands on a few standard frame building blocks, minimizing the varieties and codes of apparatus to take advantage of economies inherent in large volume production, and combining these with flexibility and versatility in a dependable, maintainable, compatible system that will provide all services wanted now and in the future.