File:Bell telephone magazine (1922) (14756254715).jpg

Identifier: belltelephonemag12amerrich (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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Text Appearing Before Image:
FiGiTiE 5. A Group of Two-wire Telephove Repeaters with Accessory Equipment.
Text Appearing After Image:
Figure 6. Group of Six 10 Kilowatt Tubes in Short Wave Radio TransmitterAT Lawrence\tlle, N. J. THE VACUUM TUBE IN TELEPHONE COMMUNICATION unrecognizable or unintelligible to the listener. Of course, onlya few circuits are as long as the New York-Los Angeles circuitbut many of the shorter circuits must be of sufficiently highgrade to be used, when needed, as parts of longer built upconnections. As mentioned earlier, the general types of tubes which aremost common in telephone plant have existed since the veryfirst. That is, their general electrical characteristics and eventheir appearance have not greatly changed through the years.In performance and economy of operation, however, the vacuumtubes of today differ as greatly from the tubes of 10 or 15years ago, as do automobiles of those same respective periods,thanks to the development work which has been carried on byBell Telephone Laboratories. The vacuum tubes in use 10 or 15 years ago had averagelives of less than one-tenth of the a

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