Results of a Medium-Speed Parallel Data Transmission Test

This paper presents the results of a data transmission test in which a data set generating nine frequency-shift channels within the voice band was employed. The tests were conducted over a cross section of the various types of facilities found in the switched telephone network. Relationships between error performance and transmission characteristics were investigated. Also correlation between errors and noise impulses was examined on a real time basis. Results include a statistical analysis of: 1 ) a distribution of error probability among calls, 2) distribution of errors among the channels, 3) error density distribution within characters, 4) number of error-free characters between successive errors, 5) probability of error-free transmission, and 6) expected character transmission rate as a function of block size.