American telegraphy and encyclopedia of the telegraph; systems, apparatus, operation (1909)
Maver, William, jr. [from old catalog] · New York, Maver publishing company · leaf 444
eck pin attached to the frame-work of the box. For other examples of the District call boxes, see the Fix combination call*and burglar alarm box. RETURN SIGNAL CALL BOXES. In the district service system described, it may have been noticed that there isnothing to tell the subscriber whether or not… … BREAK WHEEL. has been received, in the prompt appearance of the messenger, 370 AMERICAN TELEGRAPHY. But to meet the wishes of such as desire to have an immediate acknowledgement,from the central office, of the receipt of the call, various, so-called, return signals,to be actuated, automatically, or…
Telegraph
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