[asterisk-users] Fwd: Patton smartnode 463x (BRI) 25ms tail echo cancellation

[Jorge Mendoza]

Gaëtan,

The echo arise at 4w/2w conversion point, normally at the far end. Try
to call another phone number assigned to your BRI, i.e. call back to
your Asterisk server. If you use a Polycom phone to initiate the call
and another to receive the call, you have the perfect link: 4 wires with
not 4w/2w conversion. Under this test, theoretically you must not have
echo. If so, it is necessary to look elsewhere, at your Asterisk box maybe.
Modifying the rx/tx gain is a good practice too.

Best Regards

Jorge Mendoza

Gaëtan Minet wrote:
> Thanks !
>
> We installed it in the interim and have a lot of calls with far-end  
> echo :(.
> But it seems the solution could be to reduce the TX gain on our side  
> (these are using polycom phones, and  indeed  I can see a big  
> amplitude  imbalance between tx/rx on a recording). It's under test, I  
> hope it'll solve it.
>
> Kind regards,
>
> Gaetan
>
>
> On 09/09/2009, at 16:22, Jorge Mendoza wrote:
>
>   
>> Gaëtan,
>>
>> They are using as gateway to the pstn. In fact, they are remote  
>> gateways
>> for a centralized callcenter:
>>
>> [pstn] «--» [BRI] «--» [internet] «--» [callcenter]
>>
>> Regards
>>
>> Jorge Mendoza
>>
>> Gaëtan Minet wrote:
>>     
>>> Thanks
>>>
>>> Are you using these to connect isdn phones to the voip or to as a
>>> gateway to the pstn for a voip system ?
>>>
>>> Kind regards
>>>
>>> Gaetan
>>>
>>>
>>> On 08/09/2009, at 19:40, Jorge Mendoza wrote:
>>>
>>>
>>>       
>>>> We have some installations with smartnode 4554, (same tail echo
>>>> cancellation) without problems so far.
>>>>
>>>> Jorge Mendoza
>>>>
>>>> Gaëtan Minet wrote:
>>>>
>>>>         
>>>>> Hi
>>>>>
>>>>> Is anybody using these ?
>>>>>
>>>>> Gaetan
>>>>>
>>>>>
>>>>> Begin forwarded message:
>>>>>
>>>>>
>>>>>           
>>>>>> *From: *Gaëtan Minet <gminet-ml at mcit.be <mailto:gminet- 
>>>>>> ml at mcit.be>>
>>>>>> *Date: *Sat 22 Aug 2009 16:29:42 GMT+02:00
>>>>>> *To: *Asterisk Users Mailing List - Non-Commercial Discussion
>>>>>> <asterisk-users at lists.digium.com
>>>>>> <mailto:asterisk-users at lists.digium.com>>
>>>>>> *Subject: **[asterisk-users] Patton smartnode 463x (BRI) 25ms tail
>>>>>> echo cancellation*
>>>>>> *Reply-To: *Asterisk Users Mailing List - Non-Commercial  
>>>>>> Discussion
>>>>>> <asterisk-users at lists.digium.com
>>>>>> <mailto:asterisk-users at lists.digium.com>>
>>>>>>
>>>>>> Hi all
>>>>>>
>>>>>> We use pci/pci-e BRI cards in our installations. Due to echo
>>>>>> problems
>>>>>> (that was before Oslec and others), we quickly switched to cards
>>>>>> with
>>>>>> hardware-based EC.
>>>>>> So we use exclusively Digium B410p cards that provide 64ms tail  
>>>>>> EC.
>>>>>>
>>>>>> For several reasons we'd like to switch to external BRI gateways
>>>>>> like
>>>>>> the Patton smartnodes (the price is getting really close to a
>>>>>> B410p).
>>>>>>
>>>>>> I'm however curious about their HW EC. I see in the datasheets
>>>>>> that it
>>>>>> only has 25ms tail per channel (pri are 128ms, but not BRI).
>>>>>> Are some of you using these gateway and do your experience (many)
>>>>>> echo problems on calls ?
>>>>>>
>>>>>> Our other alternative is to use sangoma cards that have 128ms HW  
>>>>>> EC
>>>>>> and seem more stable overall, but it is yet a bit more expensive.
>>>>>>
>>>>>> Thanks for your feedback.
>>>>>>
>>>>>> Regards,
>>>>>> Gaetan
>>>>>>
>>>>>>
>>>>>>
>>>>>>