A Small Electronic Exchange Using Limited-Availability Switches

This paper describes a small electronic telephone exchange which employs small limited-availability configurations of reed-relay switches. A novel feature of the system is the straight wiring between the various switches, in contrast with the more usual slipped wiring between the full-availability switches of a more conventional system. The common equipment of the exchange (markers, registers, etc.) uses semiconductor and reed-relay circuits, is faster in operation than conventional electromechanical systems, and thus permits a higher traffic load per marker. One version of the equipment described has been giving public service for 200 subscribers in Leamington Spa, Warwickshire, England, since April 1965. Excellent service has been given with very few component failures and no interruption of service.