asterisk users - Apr 2004 - Echo Training Question From a Newbie

I'm running CVS code from about a week or so ago.  We've been having 
echo problems on outbound calls to the PSTN, so this weekend I enabled 
the echotraining flag in my zapata.conf.  This works great - after the 
first 3 or 4 seconds of the call.  Those first few seconds have terrible 
echo however.

I was expecting the system to remember its "training" between calls -
is
there some additional configuration flag I need to enable that?  Or is 
there something more I need to do?

Also, I read that there are alternative echo cancellation algorithms 
available - but I haven't seen a way to specify which one should be used...

Thanks!

-- 
Kevin Williams
  Senior Developer
  Applianz Technologies, Inc.
  kwilliams@applianz.com

On Monday 26 April 2004 04:53 pm, Kevin Williams wrote:
> I'm running CVS code from about a week or so ago.  We've been
having
> echo problems on outbound calls to the PSTN, so this weekend I enabled
> the echotraining flag in my zapata.conf.  This works great - after the
> first 3 or 4 seconds of the call.  Those first few seconds have terrible
> echo however.
>
> I was expecting the system to remember its "training" between
calls - is
> there some additional configuration flag I need to enable that?  Or is
> there something more I need to do?
>
> Also, I read that there are alternative echo cancellation algorithms
> available - but I haven't seen a way to specify which one should be
used...
>
> Thanks!
As I understand it, there are many characteristics of the PSTN line that are 
continuously changing.  That is the reason Asterisk "trains" on each
call.
If Asterisk did not train on each call, we would regularly get less than 
optimal results for echo cancellation.  Be sure to see the Wikki about echo 
cancellation:
http://www.voip-info.org/tiki-index.php?page=Asterisk%20x100p%20echotraining

Anon

I haven't had any responses, so I'll provide a bit more information and 
maybe someone will bite this time. :)

We're using four X100P cards to interface with PSTN and GS 
BudgeTone-100's on everyone's desks.

Echo is only an issue on calls from a SIP phone outbound on one of the 
X100P cards.

Again, the echo training does a really good job after the first few 
seconds of the call, but it has to re-train at the beginning of EVERY 
call.  Is there some way to have Asterisk remember it's training between 
calls?

Thank you,

-- 
Kevin Williams
  Senior Developer
  Applianz Technologies, Inc.
  kwilliams@applianz.com



Kevin Williams wrote:
> I'm running CVS code from about a week or so ago.  We've been
having
> echo problems on outbound calls to the PSTN, so this weekend I enabled 
> the echotraining flag in my zapata.conf.  This works great - after the 
> first 3 or 4 seconds of the call.  Those first few seconds have 
> terrible echo however.
>
> I was expecting the system to remember its "training" between
calls -
> is there some additional configuration flag I need to enable that?  Or 
> is there something more I need to do?
>
> Also, I read that there are alternative echo cancellation algorithms 
> available - but I haven't seen a way to specify which one should be 
> used...
>
> Thanks!
>