The practical telephone handbook and guide to the telephonic exchange (1906)
Poole, Joseph · New York, Macmillan Co. · leaf 517
en the red plug of Fig. 457 is inserted in the junction jacka current passes through relay R from the third conductor ofthe cord and actuates it, cutting off the line connections tobattery through relay Rr When the plug is withdrawn therelay r releases its armature and current is connected to… … Fig. 458.—Transfer Multiple{Reproduced from Electrical Engineering by permission of the Proprietors) through connection of trunk lines from one to another, eachtrunk operator or position is provided with two special transferjunction lines, these at the home position being connecteddirectly to the…
Telephone
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