File:The practical telephone handbook and guide to the telephonic exchange (1906) (14569617498).jpg

Identifier: practicaltelepho00pool (find matches)
Title: The practical telephone handbook and guide to the telephonic exchange
Year: 1906 (1900s)
Authors: Poole, Joseph
Subjects: Telephone
Publisher: New York, Macmillan Co.
Contributing Library: Northeastern University, Snell Library
Digitizing Sponsor: Boston Library Consortium Member Libraries

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required for every 2000lines, and that the switch and instrument faults average onlyabout 3 per day per 1000 subscribers; but it must be remem-bered that the exchange is comparatively new, being onlybrought into operation in 1904. The calls per subscriber perday only average about 28, which shows that there is verylittle traffic as compared with the 10 or 12 calls per subscriberper day of modern C.B. manual exchanges. Later Developments.—The improvements in the StrowgerAutomatic System of the last few years have been in the wayof central battery working and in the simplification of thecircuits and freeing the speaking line from any of the workingmagnets by arranging that the latter shall be few in numberand all connected as shunts to the main speaking line. Manyother developments have been made also in the way of party- A UTOMA TIC EXCHA NGES 52i line and trunk or long-distance line working in combinationwith manual exchanges. In order to show some of the improvements made six dia-
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f i*ST SELECTOR Fig. 479.—Theoretical Diagram of Trunk Release grams are given which have been taken from one of a longseries of articles on the History of the Automatic Telephone by A. Bessy Smith and published in Telephony of Chicago vf*nc*l C~r r^^iffi •*• ;i, . ^ xfi\— i J C*lWH WHIICM j.i#3LL ,0TA1 . «OTAB -l J>tlj SX5L is l Ws> ^I __._. ««TAHV Fig. 480.—First Selector with Trunk Release, Los Angeles of 13th March 1909. Fig. 479 shows the connections of acomplete circuit of the system as installed at Los Angeles.This figure should be compared with Fig. 477 and it will beseen that only two magnets are connected in shunt directly toany one subscribers circuit, the rest of the release magnets, etc.. 522 PRACTICAL TELEPHONE HANDBOOK RELEASE \Kvn*.

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