Maintenance Functions to Be Implemented in CCITT-MML - General Maintenance Principles - Maintenance of International Transmission Systems and Telephone Circuits (Study Group IV) 29 pp
The term “maintenance” covers all aspects which have to do with failures,such as supervision,detection,The general concepts and philosophy are fully described in Recommendation M.20.The description of the maintenance functions on the basis of Recommendation M.20 has the advantage that general descriptions of the various maintenance activities are obtained,valid for all network elements.In this case no separate descriptions for maintenance of “terminals, “subscriber lines”,“exchanges”,“lines between exchanges”,etc.are necessary.