Telephone toll system in region within radius of about 50 mi. from Chicago; 21 toll centers have been established at which are handled toll traffic of their own exchanges and 95 other exchanges in area; descriptions of toll plan and toll plant, methods of handling toll calls, volume of traffic handled, etc.
Telephone toll plant in the Chicago region
Bell Telephone Laboratories -- Reprint
1929
16 pages
7 Figs.
Article (Journal)
English
© Metadata Copyright Elsevier B. V. All rights reserved.
Telephone toll plant in the Chicago region
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