Hawkins electrical guide ... : questions, answers & illustrations : a progressive course of study for engineers, electricians, students and those desiring to acquire a working knowledge of electricity and its applications ; a practical treatise (1914)
Hawkins, N. (Nehemiah), 1833-1928 · New York : T. Audel & Co. · leaf 46
bottom of the switchboard and run through the floor of the building. THE TELEPHONE 2,139 Central Office Exchange Equipment.—This consists of the necessary apparatus for transmission and signalling between private branch exchange (P.B.X) switchboards and the exchange. In New York city there are over… … Fig. 2,945.—Operators equipment showing receiver transmitter cut in plug, etc. The breastplate transmitter equipment is shown with cords connecting it to a cut in plug and a headreceiver. The horn shaped mouthpiece is made of hard rubber and can be unscrewed andremoved. The breast transmitter is…
Electrical engineering
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