[Asterisk-Users] Tweaking AGGRESSIVE_SUPPRESSOR

[Dennis Webb]

This seems to be how AGGRESSIVE_SUPPRESSOR works.  To make sure you
don't get echo, it does what a speakerphone does, mute the other party
if it hears audio from your end.  There is a setting in mec2_const.h for
AGGRESSIVE_HCNTR=160 that says in the comments 20ms, I'm assuming this
is to tell how long to suppress the other party.  There is nothing on
this that I have found anywhere and since we are live, I can't change
until later to see how it works. 

We have Polycom SIPS for users, and it doesn't matter what the other
party is.  It seems from another thread, that the problem midcall is
that the electrical properties of the line change midcall causing the
echo to return.  Without AGGRESSIVE_SUPPRESSOR defined the first minute
or so is fine, then a click happens and the echo begins.  The phones
also seem to go extra sensitive then.  You can then hear even keyboard
clicks from typing where you don't normally.  I've wondered if it's the
zaptel cards or poor electricity at my place to the asterisk server.  I
have put in a SmartUPS 1500 to try to condition electricity there just
to make sure.

As far as echo and PRI, thanks for making me cry since I just knew that
would solve it.

On Mon, 2005-03-07 at 12:31, Andrew Kohlsmith wrote:

> On March 7, 2005 01:23 pm, Dennis Webb wrote:
> > Using TDM400's here and I have tried everything to cure the echo.  I
> > have used the Milliwatt test from the telco and from asterisk to tune
> > RX/TX gain via a patched ztmonitor.  What happens is I experience
> > midcall echo.  I turned on aggressive_suppressor and it seems to do
> > great.  The problem happens with misc. noise around the office will
> > cause it to mute the other end of a phone call while they are talking.
> > I haven't been able to find anywhere in the MEC2 source to limit when it
> > mutes the remote party.  It seems to do it with just the slightest bit
> > of sound coming from the room.  What are my options besides getting mad
> > and ordering a PRI and a TE100?
> 
> PRI and TE110 won't save you; we've had echo issues with our TE405P and a Bell 
> Canada PRI.  All the PRI does is ensure *you* are not causing echo.
> 
> Now I'm curious -- What physical phones are on either side of this call?  Do 
> you have a speakerphone on?  I've never heard of an echo canceller acting how 
> you describe, but lots of speakerphones do exactly that.
> 
> -A.
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