The practical telephone handbook and guide to the telephonic exchange (1906)
Poole, Joseph · New York, Macmillan Co. · leaf 313
e heat coil is 375 ohms. All thebars are connected to earth, and thus the line wire becomesdirectly earthed when the fuse operates. The current throughthe line is at once strengthened, and the line fuse (fitted at thepoint where the lead joins the outside line) melts, and introducesa gap in the… … Fig. 291.—Scale \ two views of the combination. The lines are connected firstto the line fuses, then to the arresters, then by jumper wire tothe horizontal frame and next to the I.D.F. When a heat coil fuses, the corresponding line inside isearthed, and its lamp is lit on the switch-board ; but as…
Telephone
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