American telegraphy and encyclopedia of the telegraph; systems, apparatus, operation (1909)
Maver, William, jr. [from old catalog] · New York, Maver publishing company · leaf 306
BRANCH OFFICE SIGNALING CIRCUIT. opens the call bell circuit and throws his own sounder, s, and key, into cireuit,by meansof which he then communicates with the branch office. This arruuoomeut has the ad- 258 AMERICAN TELEGRAPHY. vantage, if such it may be considered, that none but the main office…
Telegraph
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