[Asterisk-Users] Autodetecting faxes

[Adrian Chapman]

Asterisk wrote:
> Hmm, a little more digging got me further : I found the option 
> faxdetect=both needed to be set in zapata.conf.
> 
> Put this in. Works like a charm. Well, almost - the phone rang for about 
> three rings before the autodetect kicked in and started the fax receive.
> 
> Getting there ..
> 
> Julian.

>> I have managed to get spandsp working, and if I dial a specific 
>> extension I can receive faxes. WhooHoo.
>>
>> However, I was wanting to use the "fax detect" option in order to 
>> allow individuals to receive faxes, but can't get that to work.
>>
>> Given the following extensions (mainly copied from examples on the 
>> wiki), why is the call simply passed onto the sip device rather than 
>> being detected as a fax ?

What we found was that the fax/voice decision was being made before the 
intermittent "beep------beep------beep" fax tone was being generated, so 
it wasn't being detected.

Changing the order of things in extensions.conf around a smidge got it 
all working nicely :-

[inbound-from-pstn]
include => default
exten => s,1,Answer
exten => s,2,Wait,1
exten => s,3,Playback(thank-you-for-calling-please-wait-a-moment)
exten => fax,1,Macro(faxreceive)
exten => s,4,<Do the normal phone call gubbins>

The wait allows the start of the Playback to be heard by the caller - 
without it, we were finding the first word clipped. That second plus the 
duration of the "Thank you for calling" message gives enough time for 
the roughly 2.5sec duration between fax beeps to repeat, no matter when 
it last fell compared to the answer.

We've not checked more into the three rings before answer, but there's 
been discussion (here? elsewhere?) that it's down to the wait for caller 
ID. Try turning that off. TBH, I *like* the three rings - as a caller, 
it psychologically gives you time to get your head in gear before the 
call's answered.

Besides - If you're ringing from a mobile, it also gives you time to 
physically put the phone to your ear...

-- 
Adrian Chapman
Director
Trivas Ltd
Business on the Move
Mobility - Messaging - Infrastructure - Security - Remote Access
07796 690210 - 01582 626552