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 317
f a toll selectorwhich may serve as first, second, etc., is shown in Fig. 249. Here it is 292 A UTOMA TIC TELEPHON Y shown with a jack on the toll board. The insertion of the plug by theoperator closes the sleeve circuit to the operating relay OpRy and operatesthe visual busy signal. The operating… … Local Fig. 248.—Toll to local cord circuit, sleeve dialing. ahead, the operating wire is switched from the operating relay in thisswitch to that of the next switch. The release trunk is carried throughseparately. Toll Third Selector, with Repeating Coil.—The toll third selector,as it is called, has…
Telephone
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