Teleprinter margin and margin measurements

The CCITT (International Telegraph and Telephone Consultive Committee) has defined margin in general and different types individually. The minimum margin for a teleprinter in service, including the local end, is fixed at 35% with an error rate of 1%. The definitions of conventional distortion, conventional margin, and error rate are not in correspondence with one another. Based on a mathematical approach a proposal is made for corresponding values of these items. Methods and instruments for measuring margin are described.