[asterisk-users] Transfer to fax

[Kevin P. Fleming]

On 02/24/2012 05:20 PM, Mike Diehl wrote:
> On Friday 24 February 2012 4:06:19 pm Kevin P. Fleming wrote:
>> On 02/24/2012 05:00 PM, Mike Diehl wrote:
>>> On Friday 24 February 2012 3:17:04 pm Mike Diehl wrote:
>>>> On Friday 24 February 2012 2:39:48 pm Kevin P. Fleming wrote:
>>>>> On 02/24/2012 03:32 PM, Mike Diehl wrote:
>>>>>> Hi all,
>>>>>>
>>>>>> I've got a user that has one phone number an wants to be able to us it
>>>>>> for both voice and fax.
>>>>>>
>>>>>> When a fax call comes in, he wants to do some incantation on the
>>>>>> keypad and have the call go to the fax machine.
>>>>>>
>>>>>> As I see it, he has 3 options.
>>>>>>
>>>>>> 1.  (blind?) Transfer it to the fax extension.
>>>>>>
>>>>>> 2.  Use features.conf to create a key sequence, say *2, to
>>>>>> dial/transfer to a fax extension.
>>>>>>
>>>>>> 3.  Use fax detect (SIP) to do it automatically.  However I'm also
>>>>>> using FFA, so I suspect these are mutually exclusive.
>>>>>
>>>>> They are not. Enabling faxdetect should do exactly what you want; it
>>>>> will redirect the call to the 'fax' extension in the current context,
>>>>> and you can then Dial() your FAX machine (or send the call to
>>>>> ReceiveFAX).
>>>>
>>>> Thank you.  Then, that's what I'll do.
>>>
>>> On second though, I think my suggestion that FFA and fax detect were
>>> mutually exclusive stemmed from the idea that a call that was being
>>> originated/answered/handled by FFA would have it's call disconnected and
>>> redirected by fax detect.
>>>
>>> If this is the case, it changes my dial plan logic, and I'm not sure I
>>> fully understand what changes I'll need to make.
>>>
>>> For all I know, it might even simplify things by isolating all fax
>>> handling in one block.
>>
>> Well, first you should not have faxdetect enabled on outbound channels.
>> That takes care of the 'originating' part.
>>
>> If you have an inbound channel that you *know* you are sending to
>> ReceiveFAX, then you can just disable faxdetect on that channel before
>> doing so (this is why we made 'faxdetect' configurable from the
>> dialplan). Alternatively, you can just let calls that you *know* are
>> going to go to ReceiveFAX (dedicated FAX DIDs, for example) just 'idle'
>> in the dialplan listening to silence until faxdetect kicks in and sends
>> them to ReceiveFAX.
>>
>> Note that the usage of FFA is not relevant here; whether you are using
>> Fax for Asterisk, the free version of it, or res_fax_spandsp, the
>> behavior and scenarios would be the same.
>
> Very nice.
>
> Sounds like I need to add a faxdetect column to my SIP real-time configuration.
> Once I've done a sip reload or pruned/loaded my user agents, I should be good
> to go!
>
> Didn't know faxdetect was configurable in the dialplan...  Pointer to how to do
> it?

The CHANNEL() dialplan function with the 'faxdetect' option. Not sure 
which releases have it; it might only be Asterisk 10.

-- 
Kevin P. Fleming
Digium, Inc. | Director of Software Technologies
Jabber: kfleming at digium.com | SIP: kpfleming at digium.com | Skype: kpfleming
445 Jan Davis Drive NW - Huntsville, AL 35806 - USA
Check us out at www.digium.com & www.asterisk.org