The practical telephone handbook and guide to the telephonic exchange (1906)
Poole, Joseph · New York, Macmillan Co. · leaf 279
both-way junctions, andis shown in Fig. 264. It will be seen that 7-point break-jacks are used at each end of the line, and that in the normalcondition two equal batteries are connected to the line throughtwo double-wound 100-ohm indicators, so as to be in oppositionand neutralise each other, so… … Fig. 263.—Ringing Junction between Magneto Excl langes indicator, through both lines, the two halves of the double-wound retardation coil at the A exchange, the grid in-dicator, and. to earth through the extra spring and contactof the jack. The operator at the B exchange beingcalled by the falling…
Telephone
Internet Archive · Northeastern University Library · Public Domain Mark 1.0. Free to use for anything.
