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 221
rrent flow is reversed in the calling partys loop by the action ofthe reversing battery-connector switch with the result that the polarizedrelay P.R. swings its arm in the opposite direction, i.e., toward the coinchute and thereby causes its trigger to draw the three shunt springs intocontact with… … line <
Telephone
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