Miller, Kempster Blanchard, 1870-1933 · New York : McGraw publishing company · leaf 155
al use, it became necessary to provide meansfor opening and closing a local circuit containing the local battery,the primary of the induction coil, and the variable resistance trans-mitter. This was necessary in order to have the battery in use onlywhen the telephone instrument was being used, and… … FIG. 107.-SERIES CIRCUIT-HOOK DOWN. the receiver, its free end projected from the side of the instrumentwithin convenient reach of the user, and was provided usually witha forked hook upon which the receiver might be supported. It isfrom this hook that the name hook-switch or switch-hook has…
Telephone
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