American telegraphy and encyclopedia of the telegraph; systems, apparatus, operation (1909)
Maver, William, jr. [from old catalog] · New York, Maver publishing company · leaf 108
, connected by office wire, (that is, a pliable, insulated wire)at p, to the strap 2. j is also a spring-jack. The jack is hinged as shown, and iscapable of being moved, as at w, to permit the insertion of one or more wedges. Atthe end of the double conductor cord, remote from the wedge, the… … SINGLE SPRING JACK BOARD. The double spring-jack arrangement allows of the insertion of additional sets ofinstruments into the circuit when desired. For instance, another wedge could readilybe inserted at x^; the space between the two jacks j and j^ being, in practice, muchwider than would appear…
Telegraph
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