File:Bell telephone magazine (1922) (14775798393).jpg

Identifier: belltelephonemag23amerrich (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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Spans averaging from 350 to 450 feet, using high-strength steel wire, materially reduce construction costs phone carrier currents, being of veryhigh frequencies, can pass over thepower line simultaneously with thepower currents, without any mutualinterference, whereas this could notbe done if ordinary telephone currentswere used. 120 Bell Telephone Magazine WINTER
Text Appearing After Image:
Such a plow, pulled by a truck, buries rubber-insulated telephone wire in the ground in a single economical operation To accomplish all this, the equip-ment at the subscribers premises willprobably appear like a small table-model radio, including vacuum tubes,and with it will be associated a tele-phone. It must be provided withpower from an ordinary electric out-let and must be energized continu-ously so that it will be able to receivetelephone calls at all times. The ap-paratus at the central-office end willbe similar but slightly more compli-cated. The layout of a power linecarrier system is illustrated on pages222 and 223. To the operator at the switch-board, a power-line carrier circuit willappear no different from a wire cir-cuit. Power-line carriers will givethe same types of service as the pres-ent wire circuits. The subscriber will receive rings in the same way as overwire circuits, and will make calls tothe operator in the same way as sub-scribers on common-battery wire lines

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