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 flying spot store is a semipermanent information storage system developed for use in an electronic switching system which utilizes cathode ray tube access to information stored on photographic emulsion. Parallel optical channels are used to provide high capacity and parallel readout. A feedback system provides rapid and precise beam positioning for writing and readout. This paper describes the fundamental design considerations for memory systems of this type, stressing physical realizability, speed, capacity and other system features. The characteristics of a laboratory model are presented.
A call store is an 8,192‐word, 24‐bit per word memory system using multiaperture ferrite sheets in a destructive‐readout, coincident‐current configuration and operating in a 5.5‐microsecond read‐write cycle. It is designed for 40‐year life and operation in ambient temperatures from 32°F to 115°F.
The paper describes in detail the memory medium and memory circuits. General description is given of call store usage on the common bus in the No. 1 ESS and the maintenance and diagnostic features provided. Finally, a discussion of testing and test pattern philosophy is included, along with results measured on production stores.
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