The 1962 Survey of Noise and Loss on Toll Connections

Abstract

The 1962 sample survey of message circuit noise and loss on Bell System toll connections is described and discussed in this article. The result» are presented in terms of the distribution of noise levels on toll calls as established in the present system, the distribution of end-office to end-office losses on these calls, and the dist1'ibution of airline distances between end-offices, It is shown that the noise distribution referred to the eubscriber:« set has a mean of 19,7 dbrnc with a standard deviation of 7.8 db, that the mean of the distribution of end-office to end-office losses is 7,7 db with a standm'd deviation of 3.0 db, and that 60 per cent of all toll calls are shorter than 30 miles, while only 10 per cent span a distance of m01'e than 260 miles, The noise level Ve1'8'tlS distance and loss versus distance relaiionehip« are investigated and analyzed. The noise level is found to increase by 2.2 db for each doubling of the airline distance benceen end-offices, while the loss shows an increase of 0.6 db for each doubling of the distance. Finally, present performance of the Bell System toll plant is evaluated in terms of noise and volume grade-ofservice estimates.

Some Transmission Characteristics of Bell System Toll Connections

“…A system-wide survey of noise and loss on toll connections was undertaken in 1962. 1 The results of this survey found an important application in the setting of new over-all objectives for background noise. 2 A similar survey was undertaken in the summer of 1966.…”