asterisk users - May 2007 - Octasic echo cancellation

Hi,

I'm currently testing SoftEcho, an echo cancellation software for 
Asterisk from Octasic. I noticed an important increase of the quality of 
my coms, but I still have a few echo problems.

There is an ERL parameter which corresponds to an initial ERL value 
probably to optimize the echo training or something in that kind.

Is there a way to monitor, using one of the zttools, the instant ERL 
value, to be able to set this parameter correctly?

In that purpose, I would like to know where do the echo cancellation 
take place in the communication chain, is it after or before the 
amplification  by the Rx/Tx gain parameters? Will this gain apply on the 
echo cancelled signal or on the gross signal?

Anybody with experience on this product could give me some advice in the 
aim of removing all trace of echo?


Thanks by advance

Sebastien

Hi Sebastien,

I'm just a lowly user but I will tell you what I think I understand about
it.  

There is nothing in the Octasic documentation that suggests you can have
continuosly updated statistics but I agree that would be a nice to have
feature.  Have you tried contacting Octasic about that?

You can set the ERL and tail length in the octveqd.conf file which you need
to manually copy into the /etc/ directory as per the Octasic documentation
and octveqd.conf file included with softecho.  By default they are set to
9db and 64ms respectively.

It is my understanding EC takes place AFTER the tx/rx gain as part of the
Zaptel driver function.  Therefore your tx/rx gain WILL have an effect on
it's operation and (I think) the ERL values.

If your using Digium cards you should run fxotune and set your gains.  With
Sangoma cards you only need to set your gains.  If that is all set up ok
softecho should get rid of all your echo.   If not I would suggest you try
increase the tail length to 128ms in octveqd.conf.  I don't think you should
need to change any of the other settings. 
 

-----Original Message-----
From: Sebastien Leclere [mailto:sleclere@wirelessmundi.com] 
Sent: Monday, May 28, 2007 10:34 AM
To: asterisk-users@lists.digium.com
Subject: [asterisk-users] Octasic echo cancellation

Hi,

I'm currently testing SoftEcho, an echo cancellation software for Asterisk
from Octasic. I noticed an important increase of the quality of my coms, but
I still have a few echo problems.

There is an ERL parameter which corresponds to an initial ERL value probably
to optimize the echo training or something in that kind.

Is there a way to monitor, using one of the zttools, the instant ERL value,
to be able to set this parameter correctly?

In that purpose, I would like to know where do the echo cancellation take
place in the communication chain, is it after or before the amplification
by the Rx/Tx gain parameters? Will this gain apply on the echo cancelled
signal or on the gross signal?

Anybody with experience on this product could give me some advice in the aim
of removing all trace of echo?


Thanks by advance

Sebastien