[Asterisk-Users] strange echo problem

[Ryan Thrash]

> We have a strange echo problem.  Maybe echo isn't the correct term. 
> When we make a call f/ a SIP phone (we have several 7960's, some 
> 3coms, and I've even tried a softphone, all on the same 100BaseTX 
> network) to the pstn, if the person I'm calling has a PRI or 
> channelized T1 f/ Bell, then the sound is perfect, couldn't be better. 
> If I make a call to a person with a plain POTS line, I hear everything 
> I say in my earpiece about 1/4 second after I say it.  It's very 
> irritating.    We have tried 2 different * boxes, using 2 different 
> T1/PRI cards f/ digium.
>
> After calling digium about it, we set echotraining to 800 in 
> zapata.conf.  It got better but was still there, if I turn the volume 
> down on the phone, it does "almost" go away, but it's still 
> detectable. No where near as clear as calling a person that has a PRI 
> or channelized T1 for phone service.  The POTS persons we call that we 
> do have the echo issue with all say the call sounds perfecto to them.
>
> Am I missing something obvious?

We experience the exact same issue, and like Rich said in a subsequent 
post, I'm thinking there's a gremlin hiding somewhere in the * code. 
Everyone said you shouldn't have to even use echo canceling on a T1 
PRI, but we do or we get serious complaints, instead of consistent 
minor complaints. FWIW, it still was around in the 6/29 CVS and we just 
updated again last night.

For us the echo is a slight faint echo now that we implemented the 
echotraining=800, but it's still there. We haven't touched TX/RX gain.

We can also give anyone access and a SIP account if that would be 
helpful.

Best regards,
Ryan Thrash