File:Bell telephone magazine (1922) (14756398245).jpg

Identifier: belltelephonemag13amerrich (find matches)
Title: Bell telephone magazine
Year: 1922 (1920s)
Authors: American Telephone and Telegraph Company American Telephone and Telegraph Company. Information Dept
Subjects: Telephone
Publisher: (New York, American Telephone and Telegraph Co., etc.)
Contributing Library: Prelinger Library
Digitizing Sponsor: Internet Archive

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hand, and,on the other, to toll lines through the intervening toll testboard, carrier terminals, and repeaters. The relays and equip-ment at one end of a telephone circuit must be proper to func-tion with those at the other. Signal lamps must be lighted toindicate incoming calls and extinguished when answered; dialswitches must be operated by the switchboard dials, held untilthe conversation is completed, and released; and above all, con-versations passing through the switchboard must be clear andwithout interruption. These problems, and countless othersof a similar nature, necessitated the designing of the proper cir-cuits for the PBX to operate with the circuits already installedin the dial offices and the toll terminal room. The problemwas, in brief, somewhat similar to that of introducing a strangewheel into an old watch: much modifying had to be done. Circuit design is normally a contemplative work, calling forstudious concentration and, for best results, a relatively clois- 164
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