[Asterisk-Users] Echo Cancellation Feature

[Brent Franks]

I do feel the echo cancellation does need some work.

Currently, other than listening to users, there is no way to benchmark or
trouble shoot echo problems.

We find that 2 to 3 out of every 20 calls will experience echo.  While
echo is a problem that naturally occurs from SIP - PSTN and vice versa, I
am still baffled by the fact that the cancellation works randomly.

When doing a zap show channel X, it will also report that the cancellation
is still on.  We experience the most echo with a T100P --> Adtran TA 750
FXO modules.  While I understand these do not have impedence matching, I
wonder to myself why echo cancellation works sometimes, and others not.

Looking at Network util, processor util, and memory utilization, they do
not provide any clear indication as to why /when it occurs.

Is there anything more that can be done to debug echo cancellation, and
further are other users experiencing this random echo.  I know it was
discussed before, but the support folks at digium aren't able to offer
anymore help.

Asterisk is truly a great piece of open soruce software, and I commend the
authors/contributors for their hardware and attention to detail.

We're just a few items a way from making this thing absolutely kill the
traditional PBX market :).

Long live Asterisk,

Brent

On Thu, 22 Apr 2004, David J Carter wrote:

> I have my RX at 4.0 ant TX at 8.0,
> I get slight echo for the first 5-6 seconds then all OK.
> 
> 
> Regards
> 
> Dave
> 
> -----Original Message-----
> From: asterisk-users-admin at lists.digium.com
> [mailto:asterisk-users-admin at lists.digium.com]On Behalf Of Chris Stenton
> Sent: 22 April 2004 17:07
> To: asterisk-users at lists.digium.com
> Subject: [Asterisk-Users] inbound calls better quality than outbound
> calls on X100P
> 
> 
> I have a strange problem in that when I receive a call through the X100P
> which is forwarded to my budgetone 100 then the voice quality is perfect
> both directions. However, if I make a call out from the budgetone to the
> same caller via the X100P the sound level is a lot lower and the quality a
> lot poorer. I've had to set the rx tx gain to 1.5 or I can hardly hear at
> all.
> 
> Any ideas what is wrong, I'm using the latest zaptel and asterisk from the
> cvs head as of today.
> 
> 
> Chris
> 
> 
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