The practical telephone handbook and guide to the telephonic exchange (1906)
Poole, Joseph · New York, Macmillan Co. · leaf 516
al. Six pairs of connecting cords and plugs are alsoprovided, each fitted with a combined ringing and speaking key. Between the trunk panels is the junction panel on which arefitted the multiple junction jacks for different kinds of trunkjunctions. Fig. 457 shows the junction cord side of a pair of… … Fig. 457.—Diagram of Trunk Cord Fig 459.—Junction MultipleCircuit(Reproduced from Electrical Engineering by permission of the Proprietors) line which is normally connected to the battery through adifferentially wound relay %. The socket of the jack is norm-ally connected through a double-wound…
Telephone
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