• CCITT Rec. M.20 (11/1988) – MAINTENANCE PHILOSOPHY FOR TELECOMMUNICATIONS NETWORKS
  • 1 General
  • 2 Maintenance objectives
    • 2.1 Purpose
    • 2.2 Economics
    • 2.3 Transition from analogue to digital networks
    • 2.4 Centralized maintenance operations
  • 3 Overall maintenance philosophy
    • 3.1 Maintenance entity concepts
    • 3.2 Failure concepts
    • 3.3 Network supervision
  • 4 Bringing new international transmission systems and circuits into service
    • 4.1 Installation and acceptance testing
    • 4.2 Setting-up and lining-up
    • 4.3 Detailed considerations
    • 4.4 Bringing into service
  • 5 Maintenance phases under normal and fault conditions
    • 5.1 Performance measuring
    • 5.2 Failure detection
    • 5.3 System protection
    • 5.4 Failure or performance information
    • 5.5 Fault localication
    • 5.6 Logistic delay
    • 5.7 Fault correction
    • 5.8 Verification
    • 5.9 Restoration
  • 6 Additional maintenance activities
    • 6.1 Maintenance support
    • 6.2 Failure statistics
    • 6.3 Preventive maintenance actions
  • 7 Other maintenance considerations
    • 7.1 Reference test frequency considerations
    • 7.2 Use of maintenance test lines and loop-backs
  • References