Summary

This Recommendation provides terms, definitions, and abbreviations used in synchronous digital hierarchy (SDH) Recommendations. Physical layer terminology, synchronization-related terminology, and terms applicable to multiple technologies in addition to SDH are not included. This Recommendation contains terminology from many of the same source SDH Recommendation, but the changes were so exhaustive that one should not consider this as a simple revision of the 1999 version of ITU-T Rec. G.780. The goal of this Recommendation is to be a single normative source for terms in this subject area.