The practical telephone handbook and guide to the telephonic exchange (1906)
Poole, Joseph · New York, Macmillan Co. · leaf 271
circuit is shunted out by relay a, as thesubscriber has his telephone ofE the rest. The called sub-scriber at the b exchange has his telephone on the rest, andas the operator has depressed the machine ringing key nthere is a circuit from the earthed generator, through interrupters and front coil of… … earth. The bell is«.therefore, rung; butthere is not sufficientcurrent to actuaterelay g, and the mac-hine key is held downby electro - magnetcoils l, which areenergised by currentfrom battery throughcontact of relay g, keyN, sleeve of plug andbush of jack to cut-off relay p and earth.When the…
Telephone
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