American telephone practice (1905) (14569781288)

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

Text Appearing Before Image:

FIG. 503.—SELECTOR SWITCH, FROXT VIEW696

Text Appearing After Image:

FIG. 504.—SELECTOR SWITCH, SIDE VIEW697 698 AMERICAN TELEPHONE PRACTICE. that the rotary movement of the wipers will continue until thewipers engage a trunk line that is not in use. By this means, that is, by the first series of impulses sent overthe subscribers line in making a call, the line of the subscriber isextended through the first selector to a second selector belongingin that group of a thousand lines in which the called-for subscribersline terminates. The next series of impulses that is sent over the subscribers lineoperates in a like manner on the second selector, to cause it to pickout a trunk line extending to the connector belonging to the particu-lar group of ioo lines in which the called-for subscribers line exists.In order to accomplish this, the bank contacts on each group of 10second selectors are multipled together, and these extend by trunklines to the wipers of the connectors, the relation between the con-nectors and the second selectors being the same in this

american telephone practice 1905 strowger switches book illustrations images from internet archive library of congress

1905

Library of Congress

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public domain