Miller, Kempster Blanchard, 1870-1933 · New York : McGraw publishing company · leaf 437
at the second office through arelay at the second office to ground at the fir«t office. As the plughas not been inserted into the jack at the second office the attrac-tion of the armature of this relay will cause the lighting of thelamp at that office. When the operator at the second office… … FIG. 313.—CONNECTION BETWEEN PRIVATE-BRANCH EXCHANGE ANDCITY SUBSCRIBERS WHEREIN THE PRIVATE-BRANCH SUBSCRIBERCONTROLS THE SUPERVISORY SIGNALS AT THE PRIVATE-BRANCHBOARD. 415 416 AMERICAN TELEPHONE PRACTICE. rent over the line will cause the going out of the lamp at the firstoffice. It is evident…
Telephone
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