Summary

This Recommendation provides guidance on the effect of talker echo and its control. Talker echo is considered independently of all other impairments. Furthermore, the conjunction of talker echo and the E-model of ITU-T Rec. G.107 is explained as well as the reference to ITU-T Rec. G.108.2 on transmission planning aspects of echo cancellers is provided.

Previous versions of this Recommendation included a clause on stability that has been deleted because modern networks are largely all four-wire.

Earlier versions of this Recommendation contained several planning rules for connections with echo control devices. As many of those rules are now obsolete, they are not reproduced here.

A new Appendix III on the Combined effects of talker echo in the presence of absolute delay has been added.