. The Bell System technical journal . of these systems similar tothat used for the present coaxial system, eaeh pair of radio channels mayprovide up to (lOO telephone channels. Several pairs of such radio channelsmay be operated throuf>h the same antennas (Fi^- 10). Radio systems are also in some cases where the number of toiltriniks re(iuire(l is moderate, where diversity is desired or where wateror other natural l)arri(Ms make tiie proxision of wire circuits difficult oiimpracticable. The type of facility to be used on a particular route is sometimesaffected by re(iuirements for o
. The Bell System technical journal . of these systems similar tothat used for the present coaxial system, eaeh pair of radio channels mayprovide up to (lOO telephone channels. Several pairs of such radio channelsmay be operated throuf>h the same antennas (Fi^- 10). Radio systems are also in some cases where the number of toiltriniks re(iuire(l is moderate, where diversity is desired or where wateror other natural l)arri(Ms make tiie proxision of wire circuits difficult oiimpracticable. The type of facility to be used on a particular route is sometimesaffected by re(iuirements for other services such as teletypewriter, tele-vision network facilities, program facilities, private lines and otherfactors. Trend to Carrier Type Facilities and Advantages to Toll Sivitelling Plan About 70 per cent of the long haul toll message mileage in Bell Operat-ing Companies is provided on carrier type facilities as contrasted with7 per cent in 1930 (Fig. 11). From the transmission standpoint, carrier facilities offer marked ad-. Fig. 11—Growth in Bell iiitertoll trunk mileage showing trend towardmore extensive use of carrier type facilities. 846 THE BELL SYSTEM TECHNICAL JOURNAL, SEPTEMBER 1952
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Keywords: ., bookcentury1900, bookdecade1920, booksubjecttechnology, bookyear1
