File:Bell telephone magazine (1922) (14569717649).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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aintain communication at all times, it has beenfound desirable, therefore, to have, wherever practicable, morethan one line between cities and sections of the country andto have the lines so located that storms or accidents whichaffect the one are unlikely to interrupt service on the other atthe same time. We call these additional lines alternate routes.They are usually made up of lines which are direct connectionsbetween points other than those located on the primary route.For example, the normal routing of the seven telephone cir-cuits now in the Pittsburgh-St. Louis group is in direct cablesby way of Columbus and Indianapolis. An alternate cableroute for these circuits is by way of Cleveland, Toledo andChicago. A brief study of the accompanying maps will revealthat alternate routes have now been made available betweenmost of the important points in the Bell System. Lines are planned primarily for the handling of businessbetween the points connected and acquire important signifi- 24
Text Appearing After Image:
FicunE 1. Detailed Map Showing the Lines of the Bell System. SYSTEMS OF LONG TELEPHONE LINES cancc as alternate routes incidentally or through the workingout of plans made in advance with this feature in mind. Thesouthern transcontinental line (by way of St. Louis, Dallas,El Paso and Los Angeles), for instance, was completed bothbecause of the need for additional circuits to the southwest andbecause of the great responsibility carried by the central trans-continental line (by way of Chicago, Omaha, Denver, SaltLake City and San Francisco) when it was the only telephoneroute to the Pacific Coast. One of the reasons for installingthe first Philadelphia-Washington cable (1912) was to pro-tect service into Washington which previously had been fur-nished exclusively by open wire lines. General Circuit Design The matter of circuit design becomes of increasing impor-tance when we consider an interconnected system of routes.A specific circuit arrangement which would operate effectivelyon a di

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