Summary

Recommendation ITU-T G.703 specifies the recommended physical and electrical characteristics of the interfaces at hierarchical bit rates as described in Recommendations ITU-T G.702 (PDH) and ITU‑T G.707 (SDH). The interfaces are defined in terms of general characteristics, specifications at the output ports and input ports and/or cross‑connect points, earthing of outer conductor or screen and coding rules.

Amendment 1 adds a new Annex B that specifies an interface with high-timing accuracy (1PPS). It also updates key references to refer to the latest versions.