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 48
NE 2,141 exchanges can ring through a private branch exchange switch-board and call the party direct, when the connections have beenestablished. This is often done at night when the P.B.X. operator throws up thenight key (N.K.) and plugs into the station jack and the trunk jackwith a pair of cord,… … DROP CONTACT SPRING JACK SLEEVE Tv. JACKj*-? SPRINGS C0NMECT0R5 DROP RE5T0RIN6 LEVER Fig. 2,947.—Combined drop and jack. This affords a saving of space in switchboards andalthough it has not generally been used at P.B.X. stations, it is acknowledged to be very-satisfactory for all types of…
Electrical engineering
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