Reducing the Echo on the PSTN line of SPA3102 - it may apply to SPA122 as well (difference between SPA3102 and SPA122 may be caused by difference of default values you never modified; SPA122 defaults may not be correct for your particular environment or SPA112 hardware may be more sensitive to incorrect settings than SPA3102).
You claimed you are experiencing echo on SOME calls. So, good question seems to be: What's the difference between call experiencing echo compared with those without echo ?
By the way - it would be better to reveal some details of your's configuration and environment beyond claim "it's same". For example we don't know the call's next hop (PSTN / SIP), we don't know the codec used (if passed to SIP), we don't know you are experiencing listener echo, talker echo or both ...
I'm sorry, my English skills are so basic to understand what you are saying here.
Did you tried to follow Reducing the Echo on the PSTN line of SPA3102 (of course, references to configuration values that don't exist on SPA122 needs to be ignored) ? What result ? Did you identified what type of calls is experiencing echo (you claimed not all calls are affected) ?
Damn, I missed that SPA122 has no FXO port. Sorry.
As I mentioned in the first post the echo canceler that Sipura/Linksys/Cisco included on there previous spa products is no longer present on the SPA122.
I can't confirm nor deny your conclusion. Missing option may not mean missing echo canceller, it just may not be configurable. I suspect there has been no three independent echo cancellers even on SPA2102 - I assume there has been one with three configurable options. In the SPA122 is one echo canceller as well, but less configurable.
The reason I wrote on some calls is many carriers have an echo canceller built in on their end.
Far end echo canceller will not eliminate near end talker echo so much. You didn't revealed you are experiencing listener echo or talker echo (or both).
Well, if you verified that FXS port impedance adn other POTS line parameters are set correctly, I have no other advice for you now. May be someone else will help you better. Sorry.
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