American telegraphy and encyclopedia of the telegraph; systems, apparatus, operation (1909)
Maver, William, jr. [from old catalog] · New York, Maver publishing company · leaf 301
e single wire sends to the quadruplex, the polar relay being closed,so is ET, and, hence, the circuit via wire i, 2 and the lever of rt, is open, and therelay r responds to the signals sent over the single wire, and its ar nature controllingthe local circuit of the pole-changer, repeats the signals… … T
Telegraph
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