Bell telephone magazine (1922) (14752998251)

Identifier: belltvol20elephonemag00amerrich (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



Text Appearing Before Image:
'
Text Appearing After Image:
Telephone Receivers The desk-stand receiver, above, has been largely superseded by the handset receiver below.Differences between them are described in the text on the opposite page l9Ui Evolution by Design 147 operate. If now the contact on eachspring is spHt into two independentmembers, the chance of a particlefalling between the second set of con-tacts will also be one in a thousand;but the likelihood of two particles ofdust falling at the same time, one be-tween each of the sets of contacts,will be one-thousandth as large, orone in a million. Field experience hasindicated that with the twin contactarrangement, as used in practicewhere the two contacts are not inde-pendent, the improvement in reliabil-ity of operation is about ten-fold. xIelay springs must be properly di-mensioned and mounted. Otherwise,when they close they may bounceapart and flutter back and forth fora few thousandths of a second. Theconsequent chattering of the con-tacts results in excessive contact wear,and may