Identifier: belltelephonemag08amerrich (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:
Fig. 3. Automatic Sending Machine Telephone Typeivriters but the operator in preparing the message in this formfor transmittal can exceed this speed and, therefore,have a freedom of working which is found to be quitedesirable. This uniform speed of transmitting overthe circuit corresponds with the fastest working of mostoperators who are employed to prepare the perforatedstrip. Fig. 4 illustrates the arrangement of our presentstandard keyboard, together with a representation ofthe code combinations for each character as they ap-pear in the perforated strip used with automatic send-
Text Appearing After Image:
FiG. 4. Telephone Typewriter Keyboard and Corresponding CodeCombinations ing machines. The code always contains five elementsper character equal with respect to time and repre-sented in the electrical circuit by signaling impulsestransmitted successively by a distributor. Differen-tiation between characters is obtained by giving eachof these impulses either one or the other of two charac-teristics, and thus we have two to the fifth power or 32possible code combinations, enabling the 26 letters ofthe alphabet to be selected and necessary machine func-tions to be controlled such as the shift operation forprinting upper case characters, carriage return, etc. (183) Bell Telephone Quarterly A very desirable feature of this code is the fact thatthe same number of equal impulses is employed inselecting each character. This simplifies selectingmechanisms and makes telegraph repeating arrange-ments practicable for regenerating the telegraph im- TOTAL TELEFKCNE TYPEWRIIEB MACHINES DELIVEPiCD TO

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