[asterisk-ss7] Fax Detection with chan_ss7

[Amish]

On 08/05/2011 07:51 PM, Kevin P. Fleming wrote:
> On 08/05/2011 12:06 PM, Robert Thomas wrote:
>
>> I'm refering to the audio hook implemented to the detect the V21
>> preamble fax on the T38 gateway implementation on asterisk 1.10.
>>
>> I think it depens whether they refer to fax detection to disable echo
>> cancellation, or to renegotiate to T38.
>
> Neither. In most cases, 'FAX detection' in Asterisk used to to 
> redirect the channel to a different extension in the dialplan. This is 
> done by detecting CNG, so that the destination of the call can be 
> changed to one that is able to handle the FAX transaction. Asterisk 
> does not handle echo canceller reconfiguration for FAX at all; that's 
> done by DAHDI or the echo cancellers themselves.

Hi,

I've been using the asterisk 1.6.X. Here asterisk can only detect fax 
tones with chan_dahdi. chan_ss7, sip and iax do not detect fax tones and 
therefore do not forward the call to the fax extension. I see mention of 
NVfaxdetect on the Internet, but it looks like this code is no longer 
maintained.

I've just taken a look at chan_sip in 1.8.5, and it looks like 1.8.5 can 
detect fax tones on sip channels. Will test this out later.

Asterisk 10 is still beta, and not suitable for production - but good 
for testing.

A.