Controlled single-motion switch system operating in the London area
14 July 1933
Describes the new all rotary equipment supplied for Advance Exchange, the 51st automatic exchange to be opened in the London Area. The general principles of the bypath system are described by means of a trunking diagram, and photographs of the registers and routiners, the finder bays and the first and penultimate stage bays, together with the switch and the universal relay, accompany the paper.