[Asterisk-Users] SIP and ECHO

[Simon McAuliffe]

I've been having the same problem too, except for me it only happens
occasionnally.

I'm not 100% sure of this, but it seems that for very local calls (eg across
the city) I never get echo.  For calls that go longer distance (say 500km or
more), or through some closer call centres, I'm getting the echo.  I don't
get the echo on an analogue POTS connection to the same places (it is
clearly only happening on our asterisk system).

This might indicate some link between echo cancellation and delayed audio,
but if so, its sensitive to very small delays.

The echo can only be heard at our end, there is no trace of it at the other
end.

I'm using ATAs doing SIP to Asterisk and through a PRI connection to a
Telco.  Echo cancellation is turned on and showing as activated on the Zap
channels.  Echo cancellation is also enabled on the ATAs.

----- Original Message ----- 
From: "Brian J. Schrock" <brians at anistonetech.com>
To: <asterisk-users at lists.digium.com>
Sent: Friday, August 29, 2003 3:16 AM
Subject: [Asterisk-Users] SIP and ECHO


> Hello,
>
> I have read the information on echo and SIP in the FAQ and I have
> scoured the mailing list for possible solutions, but as yet I have not
> been able to get rid of this echo.
>
> I have a Sip phone, Digium 4 Port FXS, and 3 Digium FXO cards installed
> into an asterisk server. If I call between the Sip Phone
> (Budgettone-100) and the 4 FXS ports everything sounds great. If I call
> out to the PSTN through the FXO cards I get horrible echo, I have even
> been able when talking loud enough to get a horrible feedback loop
> going. I have tried 4 different echo cancellers in the Makefile for the
> Zap drivers and nonoe of them changed the situation.
>
> I have echocancel = (Any where from 1 - 256, I have tried alot of
> different values), and I have echocanelwhenbridged = yes.I only hear the
> echo start when the call gets bridged onto the outgoing PSTN lines.
>
> Is there anything I can do?
>
> Brian J. Schrock
>
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