Miller, Kempster Blanchard, 1870-1933 · New York : McGraw publishing company · leaf 202
r at night or atsuch times as she may not be in sight of the board, a night-alarmattachment is provided on each drop, which serves to close the cir- 180 AMERICAN TELEPHONE PRACTICE. cuit through a battery and vibrating bell whenever the shutter isdown. The small cam surface on the lower portion of… … FIG. 158.-CIRCUITS MAGNETO SWITCH-BOARD-NORMAL. nected at the central office to ground through their spring-jacks,/, and annunciators, D. Between these lines is also shown the cir-cuits and apparatus of a pair of plugs, P and F^ with their flexiblecords c and c, together with the operators…
Telephone
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