1969-70 Connection Survey: Low-Speed Data Transmission Performance on the Switched Telecommunications Network

Abstract

Error statistics of low-speed, start-stop data transmission over the Bell System switched telecommunications network are reported in this article. During the 1969–70 Toll Connection Survey, measurements were made on 534 connections with over 21 million characters transmitted, to give an overall average character error rate of 1.46 × 10−4, Over 90 percent of the low-speed test calls contained about 36,000 or 54,000 characters. A character error rate of 10−4 or less is indicated for 77.6 percent of all calls, while 95.0 percent of calls have a lost character rate of 10−4 or less. Error-free performance is shown for 48.3 percent of all calls, and 89.3 percent have no lost characters. Statistics of bursts, error-free intervals, block errors, and carrier failure durations are also presented.