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Telegraph Lines and Cables

Telegraph messages are transmitted over telegraph channels, defined2 as a "path which is suitable for the transmission of telegraph signals between two telegraph stations." These channels are provided over open-wire lines, cables, and by radio (Chapter 13). Telegraph facilities within the United States are provided by The Western Union Telegraph Company and by the Bell System.

The Western Union circuits are designed primarily for telegraph service. The open-wire mileage exceeds 2 million miles, of which about 72 per cent is copper, mostly No. 9 A.W.G., and 28 percent is iron or steel with No, 8 B.W.G. predominating.15 Cables used primarily for telegraph service are of the twisted-pair paper-insulated type. For intercity trunk-line service, No. 16 A.W.G., or larger, copper conductors are used. For local distribution purposes the cable conductors are often of No. 19 A.W.G. copper wire.

The Bell System lines and cables are designed primarily for telephone service, but simultaneous telephone and telegraph transmission is possible over many of the circuits.



Last Update: 2011-05-30