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 65
, the pull-down coil, P. D.C., more slowly draws down the plungerarm, thus thrusting the plunger into the bank. When the plunger is thrust into the bank, circuit is closed from tele-phone to the line relay of the connector, causing it indirectly to groundthe release trunk. This energizes the… … Fig. 46.—Circuit of Keith lineswitch and master switch. The release of the switch is, therefore, controlled through the releasetrunk so that whenever the connection between the release trunk andground is broken by the action of the switch ahead, which has this con-nection under control, the bridge…
Telephone
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