American telegraphy and encyclopedia of the telegraph; systems, apparatus, operation (1909)
Maver, William, jr. [from old catalog] · New York, Maver publishing company · leaf 300
-^/wwwv … Sf/z/^le nirc EDWARDS QUADRUPLEX-SINGLE WIRE REPEATER. operates the pole-changer, by opening and closing its local circuit, in accordance withthe signals transmitted. The 3-point switch is used to cut off the relay r when theattendant at repeating station wishes to communicate with a distant end of…
Telegraph
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