American telegraphy and encyclopedia of the telegraph; systems, apparatus, operation (1909)
Maver, William, jr. [from old catalog] · New York, Maver publishing company · leaf 308
coil of the indicator, the result of which is that its armature is attracted,releasing the drop. The name or call of the branch office is written on the indicator so BRANCH OFFICE SIGNALING DEVICES. 259 that, at a glance, the main office attendant can see which circuit requires attention.This… … JBram:^ Q/fcce^ Loop
Telegraph
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