1) check impedance
Impedance mismatch between the telephone and the IP Telephony gateway phone port can lead to near-end echo. The Linksys ATA device has a nearend echo canceller that compensates for impedance match. The Linksys ATA device also implements an echo suppressor with comfort noise generator (CNG) so that any residual echo is not noticeable. Echo Cancellation is configured in the Regional, Line, and PSTN Line tabs.
2) check echo options under every line
Echo Canc Enable: To enable the use of the echo canceller, select yes. Otherwise, select no.
The default is yes
Echo Canc Adapt Enable: To enable the echo canceller to adapt, select yes. Otherwise, select no.
The default is yes
Echo Supp Enable: To enable the use of the echo suppressor, select yes. Otherwise, select no.
The default is yes.
3) check echo and volume options under Regional menu
More Echo Suppression: Enable or disable more echo suppresion. The default is no.
Reduce volume via FXS Port Input Gain and FXS Port Output Gain
4) reduce (if it possible) the jitter buffer under line menu
Network Jitter Level
5) check network latency
Regards.
