ITU-T Recommendations

Recommendation ITU-T G.9701 specifies a gigabit broadband access technology that exploits the existing infrastructure of wire-pairs that were originally deployed for plain old telephone service (POTS) services. Equipment implementing this Recommendation can be deployed from fibre-fed distribution points (fibre to the distribution point, FTTdp) located very near the customer premises, or within buildings (fibre to the building, FTTB). This Recommendation supports asymmetric and symmetric transmission at an aggregate net data rate up to 1 Gbit/s on twisted wire-pairs using spectrum up to 106 MHz and specifies all necessary functionality to support far-end crosstalk (FEXT) cancellation between multiple wire-pairs, and facilitates low power operation.
Recommendation ITU-T G.9701 (2019) integrates ITU-T G.9701 (2014) and all of its corrigenda and amendments, and adds support for the following new functionality: LPM classes, optional extension of probe sequence length, short CLR/CL messages, Annex R – Showtime reconfiguration, and Appendix IV – Targeted generalized vectoring with active ITU_T G.9701 supporting lines (TGVA). It also adds several clarifications, and fixes various errors and inconsistencies including ANDEFTR support, SRA triggering and PMS-TC parameter requirements, and conditions for an rtx-uc anomaly.
Corrigendum 1 (2019) includes clarifications to clause 13.2.1.3, RPA procedure.
Amendment 1 (2019) includes enhancements to DTA functionality. Corrigendum 2 (2020) provides clarifications and corrects various errors in the Recommendation, particularly in Annex D on coordinated dynamic time assignment (cDTA).