Rec. ITU-T G.122(11/1988) – INFLUENCE OF NATIONAL SYSTEMS ON STABILITY, TALKER ECHO, AND LISTENER ECHO IN INTERNATIONAL CONNECTIONS
1 Introduction
2 Loss (a-b) to avoid instability during set-up, clear-down and changes in a connection
3 Unweighted loss (a-b) on established connections
4 Echo loss (a-b) on established connections
5 Effects of listener echo (receive end echo)
    5.1 General
    5.2 Limitation of listener echo
ANNEX A – Measurement of stability loss (a-b) and echo loss (a-b)
ANNEX B – Explanation of terms associated with the path a-t-b
B.1 Return loss
B.2 Balance return loss
B.3 Transmission loss of the path a-t-b
B.4 Stability and echo losses
B.5 Overall loudness rating of the echo path (Talker echo loudness rating, TELR)
B.6 Résumé of useful terms
References