The practical telephone handbook and guide to the telephonic exchange (1906)
Poole, Joseph · New York, Macmillan Co. · leaf 273
-$r Fig. 258.—Order Wire Junction C.B.from C.B.—Speaking Position 246 PRACTICAL TELEPHONE HANDBOOK relay J whilst the armature and … ing lamps are, however, provided contact of d are closed.When the subscriberT hangs up, relay sopens, and conse-quently relay b, asexplained previously.When the operatorhas received bothsignals, a and b, shewithdraws plugs, andthus releases armatureof relay d : lamp sutherefore glows, and B…
Telephone
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