The recommendation in view of Recommendations R.51 bis and R.54, that, for the technical supervision of international telegraph circuits, it is necessary to make periodic character error rate measurements on their international sections when they are made up of two or more channels; that certain Administrations consider it desirable to have available apparatus for making simple measurements automatically and periodically, giving an indication of the performance rating and transmitting an alarm when this rating exceeds the limits permitted for automatic switched channels.
ITU-T R.75 BIS SPANISH-1988 Referenced Document
ITU-T R.51 Standardized Text for Distortion Testing of the Code-Independent Elements of a Complete Circuit - Telegraph Transmission (Study Group IX) 2 pp*， 1989-01-01 Update
ITU-T R.54 Conventional Degree of Distortion Tolerable for Standardized Start-Stop 50-Baud Systems - Telegraphy Telegraph Transmission (Study Group IX) 4 pp*， 1993-01-01 Update
ITU-T R.75 BIS SPANISH-1988 history
1988ITU-T R.75 BIS SPANISH-1988 MAINTENANCE MEASUREMENTS OF CHARACTER ERROR RATE ON INTERNATIONAL SECTIONS OF INTERNATIONAL TELEGRAPH CIRCUITS