[Asterisk-Users] SIP phones unbeatable echo

[Eric Bishop]

Would you mind sharing with the list the tellabs hardware and how you got it
up and running (ie pinouts etc)?



On 1/15/06, gw at adcomcorp.com <gw at adcomcorp.com> wrote:
>
> Hello Dan,
>
> I was fighting with echo on a number of circumstances, and came to the
> following conclusions.
>
> If you are on a distant loop, or analog lines with issues, those issues
> need to be addressed or you need a workaround.
>
> In a few cases, I converted to ISDN-BRI, which has been one of my best
> decisions, because I get excellent quality as well as high-speed call
> completion...
>
> In one case, I put in an ADIT 600 channel bank, and still had serious
> echo problems. I tried and tried, but found no simple solution by
> messing with the zapata drivers.  Installing a hardware tellabs echo
> canceller totally solved the echo issue.  I have the zapata.conf echo
> cancellation totally off, and the lines sound great.  These are also
> lines that are odd, meaning about 15K feet from the CO, with periodic
> instabilities during rain/snow.
>
> I went through the various tweaks, milliwatt tests, etc, but only the
> hardware could solve it (and in minutes after installation as opposed to
> the hours I spend working with software).
>
> Depending on the amount of channels you have, you may consider a
> channelbank with tellabs, or one of the new digium analog cards with ec,
> though I have not used the new digiums yet myself.  They are expensive
> solutions, but the best solutions too.
>
> I wish there were 4 port card that had great EC, but there isn't.  I
> wait for the day that we have pci-express voip cards at our disposal,
> that would be something...  Asterisk would take off entirely at that
> point, since the latencies that cause so many problems would be gone,
> and the capacities would be so much higher.
>
> Just in case I went over your head here, sip>sip should produce no echo.
> If it does there are other issues.  If you are going analog>analog and
> hear no echo, I would have a look at the network itself.
>
> Regards,
> Greg
>
> -----Original Message-----
> From: asterisk-users-bounces at lists.digium.com
> [mailto:asterisk-users-bounces at lists.digium.com] On Behalf Of Dan Elder
> Sent: Thursday, January 12, 2006 2:53 PM
> To: asterisk-users at lists.digium.com
> Subject: [Asterisk-Users] SIP phones unbeatable echo
>
> Hey all again, I'm wrestling with echo problems on our sip extensions.
> I've set these items in zapata.conf but tweaking these values doesn't
> seem to make much difference
>
>
> echocancel=yes
> echocancelwhenbridged=yes
> echotraining=2500
> rxgain=8.0
> txgain=1.0
>
>
> are there other settings that can help me tame this beast? Been
> searching but not turning up anything that'll work here.
>
> Thanks in advance.
>
> _______________________________________________
> --Bandwidth and Colocation provided by Easynews.com --
>
> Asterisk-Users mailing list
> To UNSUBSCRIBE or update options visit:
>    http://lists.digium.com/mailman/listinfo/asterisk-users
> _______________________________________________
> --Bandwidth and Colocation provided by Easynews.com --
>
> Asterisk-Users mailing list
> To UNSUBSCRIBE or update options visit:
>    http://lists.digium.com/mailman/listinfo/asterisk-users
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://lists.digium.com/pipermail/asterisk-users/attachments/20060116/5d4a3f1f/attachment.htm