[Asterisk-Users] Local Echo

Matt Fredrickson
Tue, 12 Apr 2005 16:21:12 -0000

On Tue, Apr 12, 2005 at 10:16:16AM -0700, Noah Silverman
wrote:
> I have a strange echo problem.
>
> When speaking on the phone with someone, I hear MY OWN voice with a
> sever echo.  The other party sounds perfect, and they can hear me
> perfectly.  It is as if only the sidetone has an echo.
>
> I'm running * on a dedicated box, small LAN, and am using 4 FXO cards
to
>  connect the box to PTSN lines.  My phones are Polycom IP500 SIP phones.
>
> The only echo cancellation stuff that I can find relates to cancelling
> echo between my system and the PTSN lines.  Since the call is
"perfect",
> I don't see how this would apply.
>
> Any suggestions??

If you're using a TDM card, you might see if the fxotune program will help.

It does impedance tuning of the card and finds the line impedance that has
the lowest mean power (i.e. least echo).  I've been working on it for a
while
and some people have had some success with it.

Matthew Fredrickson