The central control is composed of thousands of relatively simple logic circuits, intricately interconnected to perform the primary data processing functions of the No. 1 electronic switching system. This paper discusses both the circuit development of the basic modules and their application to the logic design of some of the high‐speed arithmetic circuits required in the central control. Special electrical design features, wiring rules, and circuit pack assignment procedures are also described.

The advent of electronic switching has necessitated a considerable number of changes in the circuit design philosophy employed in the electromechanical switching art. The invention of the transistor and the refinement of other semiconductor devices have made possible new techniques. This paper discusses the philosophy of circuit design for the central control of an electronic switching system. Primary emphasis in the designs has been low cost consistent with good margins, reliability and the meeting of systems requirements.

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