[Asterisk-Users] TE411P Really Bad Echo

Sat Feb 11 07:15:37 MST 2006

Yes, right now we are only using span 1 on the quad span card with plans 
to pull in another T1 PRI when we get this echo problem solved.  The 
echo is only experienced when the call terminates to traditional analog 
circuits both local and long distance.  Calls to cell phones, and other 
known digital circuits do not exhibit the symptoms.  I've been sent a 
few articles off list which discussed the reasons why this may occur, 
imperfect impedance where the digital circuit is switched to the analog 
circuit.

In testing I've set echocancel=no made calls, and echocancel=yes and 
made calls with no real audible difference.  I haven't done a zap show 
channel while on a call with echo, but I plan to this weekend.  I was 
informed that the number of taps would be shown.  I used a stop watch 
last night to try to get the delay, and it was about 1/2 to 1 second 
delay and was continual so long as I was talking.  It wasn't affected by 
differing acoustical variations.  I tested this using handset, headset, 
and speakerphone.  Disabling VPM and recompiling zaptel or removing the 
VPM off the board completely is the only thing that has any effect on 
the echo.  Hopefully the zap show channel will provide to me another 
data point to help me determine if the HW module is active.

More to come...

Stagg Shelton
www.oneringnetworks.com

Cory Andrews wrote:

> Stagg - I know you get a full 128ms tail of echo can on the Sangoma.  
> I believe that on the TE411P, the 128ms tail is shared by all (4) 
> spans, and as you add additional spans up to maximum of 4, the echo 
> can tail amount decreases accordingly.  If you are running 4 spans, 
> you have 32ms of echo can tail on each span, not the full 128ms.
>  
> Now that I'm reading back through your post thread, it looks like you 
> were only running 1 span on the TE411P, so you should have been 
> getting the full 128ms of echo can tail.  You may not find an 
> improvement with the Sangoma.  I have never experience, nor heard of a 
> 1-2 full second delay.  Trial and error is likely your course of action. 
>  
> Cory J Andrews
> ++++++++++++
> VOIPSupply.com
> 454 Sonwil Drive
> Buffalo, NY 14225
> ++++++++++++++
> voice - 716.630.1555 X22
> email - Cory at VOIPSupply.com <mailto:Cory at VOIPSupply.com>
> AIM - B2CORY
>
>     ----- Original Message -----
>     *From:* Stagg Shelton <mailto:asterisk at oneringnetworks.com>
>     *To:* Asterisk Users Mailing List - Non-Commercial Discussion
>     <mailto:asterisk-users at lists.digium.com>
>     *Sent:* Friday, February 10, 2006 11:34 PM
>     *Subject:* Re: [Asterisk-Users] TE411P Really Bad Echo
>
>     It was Digium's opinion that perhaps the card had a VPM.  We got a
>     replacement TE411P, I implemented it tonight and still the exact
>     same echo problem.  At this point I feel like I can rule out
>     failed hardware. 
>
>     I contacted Digium support and now they are telling me it's
>     something with my carrier, and I should call them.  I called
>     Bellsouth, and they ran a full stress test on the circuit taking
>     me offline for about 30 minutes. 
>
>     The end result is that the circuit test passed with no errors. 
>     Bellsouth says it's not in their network, Digium says its not
>     their card, and I have a te411p with VPM disabled in the wct4xx
>     kernel module because something doesn't work the way it should. 
>     My customer is wanting to know about sangoma cards with the echo
>     cancellation, and at this point I'm nervous to recommend any
>     hardware.  I'm going to look into the sangoma that you suggested. 
>     Are there any other kinds of products that I could look into
>     either Passive or Active.
>
>     Thanks
>
>     Stagg Shelton
>     www.oneringnetworks.com
>
>
>     Matt wrote:
>
>>try sangoma carrier grade 104d hardware EC card. we're using it ourself.
>>
>>Best Regards
>>
>>Matt
>>----- Original Message ----- 
>>From: "Anthony Rodgers" <Anthony_Rodgers at dnv.org>
>>To: "Asterisk Users Mailing List - Non-Commercial Discussion"
>><asterisk-users at lists.digium.com>
>>Sent: Tuesday, February 07, 2006 12:57 PM
>>Subject: Re: [Asterisk-Users] TE411P Really Bad Echo
>>
>>
>>  
>>
>>>For what it's worth, we have been going through very similar issues
>>>with a TE411P - with Digium support, we have basically gone as far as
>>>we can with the HW EC, and are now using MG2 with much better results.
>>>
>>>We have a Ditech EC box on order.....
>>>
>>>Regards,
>>>-- 
>>>Anthony Rodgers
>>>Business Systems Analyst
>>>District of North Vancouver
>>>Web: http://www.dnv.org
>>>RSS Feed: http://www.dnv.org/rss.asp
>>>
>>>
>>>On Feb 7, 2006, at 7:36 AM, Matthew Fredrickson wrote:
>>>
>>>    
>>>
>>>>On Feb 5, 2006, at 9:36 PM, Stagg Shelton wrote:
>>>>
>>>>      
>>>>
>>>>>I just implemented a system using a TE411P hardware echo cancellation
>>>>>card. Per Digium, I setup zaptel.conf, and zapata.conf the same way
>>>>>        
>>>>>
>>>>as
>>>>      
>>>>
>>>>>I always have. To my surprise calls out to the PSTN had a terrible
>>>>>echo. 1 - 2 second delay, and quite clear. The echo was so bad that
>>>>>        
>>>>>
>>>>I
>>>>      
>>>>
>>>>>had to remove the hardware echo cancellation module from the card.
>>>>>        
>>>>>
>>>>We
>>>>      
>>>>
>>>>>are only using the 1st span of this card right now, and we have a
>>>>>tdm400p with 4 fxs modules installed as well.
>>>>>
>>>>>If anyone has experience with this card, can you tell me if I am
>>>>>missing
>>>>>something.
>>>>>        
>>>>>
>>>>1 to 2 seconds?! That's ridiculously huge. I don't think you'll find
>>>>a echo canceler anywhere that can fix your echo problem. If it gets
>>>>better with the VPM disabled, then definitely contact Digium
>>>>tech-support about it.
>>>>
>>>>Matthew Fredrickson
>>>>
>>>>_______________________________________________
>>>>--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
>>>
>>>
>>>    
>>>
>>
>>_______________________________________________
>>--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
>
>------------------------------------------------------------------------
>
>_______________________________________________
>--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/20060211/927f6d54/attachment.htm