[asterisk-users] T38 fax detection using g729

[Larry Moore]

On 14/04/2011 6:57 PM, Niccolò Belli wrote:
> Il 14/04/2011 12:25, Larry Moore ha scritto:
>> I made a suggestion on how you could check this i.e. have your incoming
>> call go directly to the fax extension, my 1.8.3.2 installation
>> immediately negotiates a T.38 connection in this sceanrio, of course I
>> enabled the fallback option so it will use g711a if T.38 is not accepted
>> by the peer.
> Yeah, I know, I just didn't have time to check it. Now I've just
> finished checking and Eutelia DOESN'T send any T.38 re-invite :(
> I hoped it was an asterisk bug because there was a chance it may be
> solved, now that I know it's an Eutelia problem I know it will never be
> fixed.
> I sent them an e-mail but I already know the answer: "T-38-what?" -.-
>
It could possibly work,

sip.conf

[general]
.
.
preferred_codec_only=no
disallow=all
allow=alaw,g729 ; alaw required for T.30 facsimile if T.38 fails to 
negotiate
faxdetect=no
t38pt_udptl=yes,redundancy,maxdatagram=400
.
.
[eutelia]
language=it
type=peer
host=voip.eutelia.it
username=my-eutelia-number
fromuser=my-eutelia-number
secret=my-secret
qualify=yes ;ping per controllo stato
directmedia=no ;asterisk viene sempre usato come media proxy
dtmfmode=auto
insecure=invite,port
context=eutelia-in
callbackextension=s
faxdetect=yes
t38pt_udptl=yes,redundancy,maxdatagram=400


N.B. I use callbackextension in the peer config rather than register in 
the general section.

I use extensions.ael rather than the .conf version hence I would use 
something like this

context eutelia-in {

     s => {
         Set(CHANNEL(language)=it);
         Answer();
         Ringing();
         Wait(8);
         Dial(SIP/159,,30);
         Hangup();
         };

     fax => {
         Set(FAXFILE=/var/spool/asterisk/fax/prova4.tif);
         ReceiveFAX(${FAXFILE},f);
         Hangup();
         };

Larry.