[Asterisk-Users] Echo cancellation, when software doesn't cut it. Whats next?

[Billy Huddleston]

I failed to mention I'm using a Cisco 2600 with Sip Re-invites.. and YES, I
do have the echo can on the Cisco turned on, The echo is SOOOO bad, it's not
even touching it...  When we place 1-800 calls or call LD via our offnet
provider, everything works fine, it's just with local calls on the PRI...
We found out that the 1-800 #'s go out our carriers Sonus switch (a VoIP
switch) which has 128ms Echo Can in it...  Hmmm...

Thanks, Billy

----- Original Message ----- 
From: "Brent Franks" <mwless at mindworks.net>
To: <asterisk-users at lists.digium.com>
Sent: Thursday, July 01, 2004 12:16 PM
Subject: Re: [Asterisk-Users] Echo cancellation, when software doesn't cut
it. Whats next?


> On Thu, 1 Jul 2004, Mike Benoit wrote:
> > Obviously the less I spend the better. But if we have to, a few thousand
> > more I guess. The problem I have is that this setup is more of a "trial
> > run". Once it works, I'm going to be cloning slightly smaller setups to
> > 9 other cities. But they are pretty small, 1 or 2 lines and 2-4 phones
> > in each location.
>
> I totally understand this.  My users complain frequently about echo, and I
> am still unable to determine why sometimes it works great, other's it does
> not.  The CPU and Memory are powerful enough to handle it, and we rarely
> ever see any load on the box.
>
> I too feel this is the major caveat to Asterisk right now.  I am curious
> how anyone is achieving a near echo free system.  We are shooting for 1
> out of every 300 calls to have echo, which I think can be a realistic
> goal.  Given the nature of open source, and the mix-and-match of
> components that come up, I can see where Digium is in a hard place to nail
> down the cause of every occurance.
>
> >
> > I will only be using POTS lines in each location.
> >
> > The current setup works great besides the echo, and some of the
> > information I've read point to the Telco being the issue. If thats the
> > case, I should in theory be able to get them to fix the problem. (though
> > I could be dreaming)
>
> I think ultimately, if a Mediatrix box, or Cisco box can accomplish echo
> cancellation, Asterisk should be able to do it with as much success.
> Being that I am not an experienced Programmer, I try not to complain to
> loudly.  With my level of involvement, I typically make the business case
> to customers and spec out ROI, etc.  I do have a technical background, and
> am getting better at trouble shooting Asterisk and working on the source
> code.  In fact, subscribing to the CVS list has taken me leap years ahead
> of understanding the changes and why they are being committed.
>
> I don't know how much more putting a DSP to handle echo can on the cards
> would cost, but if it were 400 - 500 more I would certainly pay it without
> a second thought, provided it worked.  Echo, I think, is the largest draw
> back to VoIP, and will be the limit to entry into many businesses.  I know
> my client, if they were to do it all over again, would choose a regular
> TDM (nortel, avaya) solution over the echo they are experiencing.
>
> I think asterisk is definitly headed in the right direction though, and
> nothing good comes over night.  So everyone who has worked on it deserves
> to be commended.  Without their insight and dedication, we wouldn't even
> be talking about this, or have alternatives to turn to.
>
> Regards,
>
> - Brent
>
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