File:Bell telephone magazine (1922) (14753257611).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

View Book Page: Book Viewer
About This Book: Catalog Entry
View All Images: All Images From Book
Click here to view book online to see this illustration in context in a browseable online version of this book.

Text Appearing Before Image:
ects of local battery supply under these conditions led to theintroduction of the common battery or central energy type oftelephone and central office equipment in the more denselypopulated areas. The evolution of the common battery telephone has producedtwo types of service, manual and dial. Dial service is of twogeneral types: the power driven panel, used in large multi-office areas; and the step-by-step, usually employed in mediumsized and small exchanges and for dial private branch ex-changes. With the common battery instrument in general use com-mercially, the furnishing of power became a more and moredifficult problem. It is apparent that the electric power re-quirements for the operation of two telephones over one pairof wires are not great. However, when it is considered thatthe number of telephones operated from a single office is veryoften in excess of 10,000, any part of which may be in usesimultaneously, it will be realized that a real power supplyproblem is presented. 290
Text Appearing After Image:
The Power Room of the Wasiiinciun, D. C, Disiku i-Mi.ikuiui.iiA.\-N.\uu.\.\LDial Offices, Showixo Charging Machines in the Foreground and Ringing Ma-chines IN the Right Background.

Note About Images