Automatic telephony; a comprehensive treatise on automatic and semi-automatic systems (1921)
Smith, Arthur Bessey, b. 1875, Campbell, Wilson Lee · New York : McGraw-Hill · leaf 232
the circuit of the Christensen selector employed onorder wires from A operators positions to B operators positions.The selector is also used between A operators positions and toll-recording positions, between A operators positions and informationoperators, etc. The operation of the circuit between… … Fig. 192.—Circuit of automatic order wire system. of electromagnet A to earth. Relay U disconnects the operators tele-phone circuit from the listening keys of her cord circuits thus automat-ically cutting off the waiting subscriber while a B operator is selectedand given the subscribers order. The…
Telephone
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