[Asterisk-Users] Local Echo

Johann
Wed, 13 Apr 2005 14:04:43 -0000

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??
>
>-N
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>
We have a similar problem.  We are using Polycom IP600 phones with a PRI
line.  Randomly there will be the sidetone for an agent answering the
queue on the call.  I have used ZapScan and do not hear the echo
either.  It is just the agent's voice echoed back.  I have so far been
unable to reproduce the echo from external lines I test with.  The other
end never hears it.

Since the problem does not happen to all calls, I not altered the
rxgain/txgain in zaptel.conf yet.  It almost seems like there is some
qwirk with Polycom's DSP and asterisk that is causing it.

The users haven't been reporting it as much now either.  So either they
got sick of telling me and not having it fixed or whatever caused it is
gone.

--johann