File:American telephone practice (1905) (14755982342).jpg

Identifier: americantelepho00mill (find matches)
Title: American telephone practice
Year: 1905 (1900s)
Authors: Miller, Kempster B. (from old catalog)
Subjects:
Publisher:
Contributing Library: The Library of Congress
Digitizing Sponsor: The Library of Congress

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Text Appearing Before Image:
OUT-GOING TRUNK FIG. -STROMBERG-CARLSON TRUNK CIRCUIT. called for, the following conditions will exist: The relay, A, willbe operated by current flowing from the battery through the wind-ing of the relay, S3, to ground, through the winding of relay, A.The operation of the relay, A, will cause the flow of current fromthe ungrounded side of battery through the coil of relay, B, to thecenter point of the outgoing trunk repeating coil, thence over bothsides of the trunk line in multiple to the center point of the incom-ing trunk repeating coil, thence to ground through the relay, C, atthe incoming trunk end. The relay, C, will thus be operated, butthe relay, By will not be operated because of the very high resistanceof the winding of the relay, C, through which the relay, B, is notcapable of acting. It will thus be seen that the relay. A, at the 4V#r
Text Appearing After Image:
l#K FIG. 293.—CONNECTION BETWEEN TWO SUBSCRIBERS THROUGHTWO OFFICES—STROMBERG-CARLSON SYSTEM. 374 TRUNKING SYSTEM BETWEEN COMMON BATTERY OFFICES. 375 outgoing end, and the relay, C, at the incoming end will be ener-gized when the A operator plugs into the outgoing jack, and willremain energized as long as the connection remains at the outgoingend. The operation of the relay, C, closes the circuit of the dis-connect lamp, this circuit being traced from the negative side ofbattery at the second office through the disconnect lamp, theleft-hand back contact of the relay, D, to ground through the con-tact of relay, C. The energization of relay, C, also causes the il-lumination of the ringing lamp, current flowing from the negativeside of battery through this lamp, the back contact of relay, E, theclosed right-hand contact of relay, D, to the grounded side of bat-tery through the closed contact of the relay, C. The calling supervisory lamp in the A operators cord circuitwas illuminated

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