[Freeswitch-users] fax detection

[Michael Jerris]

You have access to the full sdp in channel vars, so you can condition  
on those with regex.

Mike


On Sep 17, 2009, at 6:25 PM, Tihomir Culjaga wrote:

> Hi Michael, thanks for your response.
>
> i think it will be enough to check the call capability... we always  
> know the call is fax. We just need to apply the correct protocol :P
>
>
> let's suppose you have 2 incoming calls:
> SDP containing G711, gsm, T.38 caps
> SDP containing G711, gsm caps
>
> the caps will be known on within INVITE message and FS can act  
> accordingly.
> If there is no T.38 support within SDP, start fax application  
> (SpanDSP).
> If there is T.38 suport within the SDP, route the call to some  
> predefined gateway meant for T.38 fax receiving.
> In both cases, the fax should be received :P.
>
> So, any chance to route the call according to T.38 caps within SDP  
> message?
>
>
>
> Now, for sending faxes there is some challenge.... we still have 2  
> calls:
>
> we start sending a fax inband (SpanDSP) as this is the only thing we  
> know... and:
> if we receive 200 OK with SDP containing G711, anyCaps => continue  
> with InBand Fax
> if we receive 200 OK with DSP containing anyCompressedCaps, T.38 =>  
> drop the call without sending ACK to 200 OK ... and move the fax to  
> be sent into a different directory.
> well, as i said, while receiving faxes will work 100%, sending is  
> tricky... but it might work.
>
> what do you guys think?
>
> T.
>
>
>
>
> On Thu, Sep 17, 2009 at 10:51 PM, Michael Collins  
> <msc at freeswitch.org> wrote:
>
>
> On Tue, Sep 15, 2009 at 8:45 AM, Tihomir Culjaga  
> <tculjaga at gmail.com> wrote:
> Hi,
>
> is there any way to route fax calls according to the call capability?
>
> I mean .. if the fax call supports T.38 i'd like to route it to a T. 
> 38 capable gateway. All other fax calls (meaning inband) should be  
> handled by FS/SpanDSP.
> Of course, I know that every fax call starts as a voice call and  
> upon fax tone detection additional capabilities are being negotiated 
> (T.38 or G711). Can it be done in early media, before the call is  
> even answered?
>
> I don't claim to be an expert in all this, especially T.38, but if I  
> understand correctly, in both cases the call needs to be answered  
> first. I'm pretty sure that the sending fax machine won't start  
> emitting the 1100Hz tone until the receiving end answers. Also, with  
> T.38 doesn't the call have to come up and then T.38 gets negotiated?  
> (I don't know, I have only read about it.)
> -MC
>
>
> So, here the goal is to have a T.38 capable GW handling T.38 calls  
> while SpanDSP handling T.30...
>
>
> Any chance to do that with FS?
>
>
>
> _______________________________________________
> FreeSWITCH-users mailing list
> FreeSWITCH-users at lists.freeswitch.org
> http://lists.freeswitch.org/mailman/listinfo/freeswitch-users
> UNSUBSCRIBE:http://lists.freeswitch.org/mailman/options/freeswitch- 
> users
> http://www.freeswitch.org
>
>
>
> _______________________________________________
> FreeSWITCH-users mailing list
> FreeSWITCH-users at lists.freeswitch.org
> http://lists.freeswitch.org/mailman/listinfo/freeswitch-users
> UNSUBSCRIBE:http://lists.freeswitch.org/mailman/options/freeswitch- 
> users
> http://www.freeswitch.org
>
>
> _______________________________________________
> FreeSWITCH-users mailing list
> FreeSWITCH-users at lists.freeswitch.org
> http://lists.freeswitch.org/mailman/listinfo/freeswitch-users
> UNSUBSCRIBE:http://lists.freeswitch.org/mailman/options/freeswitch- 
> users
> http://www.freeswitch.org

-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://lists.freeswitch.org/pipermail/freeswitch-users/attachments/20090923/874ef2f6/attachment-0002.html