Miller, Kempster Blanchard, 1870-1933 · New York : McGraw publishing company · leaf 661
FIG. 468.-WIRE CHIEFS TESTING TRUNK. drops, D and D, are provided, which are under control of the insideand outside lines respectively. Thus, while such a connection is upat the main distributing board, if the operator at the switch-boardsends calling current out on the line, the drop, D, will… … FIG. 4G9.-WIRE CHIEFS THROUGH CONNECTING CORDS. If, on the other hand, a subscriber attempted to call the exchangethe drop, D, would fall. In either case the wire chief could answerby plugging into the jack, / or /, with the plug, p, of the through..connecting cord circuit shown in Fig. 469, and…
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