[asterisk-users] Disabling Echo Cancellation on a per Call basis

[Tobias Wolf]

Hello,

just want to bring this question up again.

Is someone able to tell me, yes you can disable echo can on a per call basis and 
it is done this way, or not it is not possible, go away ...

If it is not possible, why is that so ? Is there really no need to do this and i 
am totally mistaken?

Generally receiving faxes works fine, but sometimes they break and i assume i 
might have something to do with echo can.

Kind Regards,

Tobias

Tobias Wolf schrieb:
> Olivier schrieb:
>>
>> 2009/2/10 Tobias Wolf <tobias.wolf at evision.de 
>> <mailto:tobias.wolf at evision.de>>
>>
>>     Hello all,
>>
>>     i was just made aware on the Bristuff-Mailing list, that it is
>>     possible to
>>     disable echo cancellation per dialplan application.
>>
>>     This comes in very handy, for terminating faxes.
>>
>>     But the application seems only to be existing in the bristuff patches.
>>
>>     Does there exist a solution for
>>
>>     Asterisk 1.6.0.3
>>     Digium Wildcard TE110P T1/E1
>>     DAHDI Version: 2.1.0.3 Echo Canceller: MG2
>>
>>     without any Bristuff?
>>
>>     At the Moment i have fax detection enabled.
>>
>>
>> Do you mean a given DID receives voice or fax calls ?
>> If positive, which app is detecting faxes ?
> 
> Since i have a dedicated DID for fax calls, i don't really need the fax 
> detection. For this number i simply start the ReceiveFAX-Application and have 
> some voodoo around it to name the file correctly.
> 
> But if i do this, and look into the channel information from Dahdi i see that 
> the fax handled flag is set to no. And this seems wrong to me. I have the 
> feeling that the percentage of failed faxes is higher is this flag is set to no 
> (or false, can't remember) ...
> 
> Since i have a PRI connected to my Asterisk, i use the built-in fax detection of 
> DAHDI. I have enabled it for incoming fax calls, in chan_dahdi.conf
> 
> faxdetect=incoming
> 
> The incoming call is answered and with an included Wait(4) the fax is detected 
> and switched to the fax extension, where the ReceiveFAX-App is executed.
> 
> Now the fax handled flag is set to yes and i am able to receive most of the fax 
> calls. But i have massive problems receiving fax calls from certain people, 
> especially from UK (i am in germany). I am not quite sure, if the echo canceller 
> is automatically disabled if DAHDI knows that the call is a fax and the channel 
> info doesn't indicate otherwise, since it says that echo canceller is active 
> even if it says that it handles an fax.
> 
> This is the reason why i was so happy to hear, that there seems to be the option 
> to control the echo canceller with an dialplan app. But since this seems to be 
> an Bristuff-only feature i am a little bit stuck.
> 
> Kind regards,
>