The practical telephone handbook and guide to the telephonic exchange (1906)
Poole, Joseph · New York, Macmillan Co. · leaf 602
oses amomentary battery circuit through supervisory lamp (or lamprelay) sl, sleeve contact of answering plug ap, socket ofanswering jack lj, coil of cut-off relay ur to earth. The arma-ture of ur is attracted and the calling lamp (or relay) is cutoff; and at the same time the supervisory lamp is… … Fig. 517.—Connections of L. M. Ericssons C.B. System usual manner by connecting into one of the multiple jacks mj,and the speaking circuit is completed through two condensers.The operator is provided with combined listening and ringing 574 APPENDIX keys, and the latter keys are arranged for…
Telephone
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