[asterisk-users] Sipgate > DTMF not detected by Asterisk 1.6 [dtmfmode=rfc2833]

[listuser at spamomania.co.uk]

On Wed, 2010-01-13 at 10:12 -0500, Kristian Kielhofner wrote:
> On Wed, Jan 13, 2010 at 2:43 AM, listuser at spamomania.co.uk
> <listuser at spamomania.co.uk> wrote:
> > Thanks for that. Looking at the RTP packets I can see two types as you
> > point out. The first appears to be the audio:
> >
> > Real-Time Transport Protocol
> > 10.. .... = Version: RFC 1889 Version (2)
> > Payload type: ITU-T G.711 PCMU (0)
> >
> > And as you say, the DTMF events are clear to see:
> > RFC 2833 RTP Event
> > Event ID: DTMF One 1 (1)
> > ..00 1010 = Volume: 10
> >
> > So, as these can be seen in the stream, do I need to tell Asterisk to
> > detect these? Does it not do that when I set: dtmfmode=rfc2833
> > ???
> 
>   There are some pretty widely recognized RFC2833 compatibility issues
> in the SIP/RTP world.
I had a nasty feeling something like that was coming :-(

>  Which version of Asterisk are you using?  
Asterisk 1.6.1.11


> Do
> you know what kind of equipment your carrier is using?  If they are
> using Asterisk you can try to add rfc2833compensate=yes to their peer
> entry in sip.conf.
I've not been able to get that out of them, but I don't *think* It's
Asterisk based because they say:
"Unfortunately, our assistance with Asterisk is extremely limited. For
configuration problems you will have to rely on other sources."
[http://www.sipgate.co.uk/faq/index.php?do=displayArticle&article=540&qw=asterisk]
> 
> >>
> >> The SIP debug, however, will tell you if the remote end is configured
> >> to use RFC2833 or not.  That's why I was telling you to look for
> >> telephone-event in the INVITE from your provider.  Keep in mind SIP
> >> (most likely) runs over UDP between you and your provider, not TCP.
> >>
> > I see a 'telephone-event' :
> >
> > a=rtpmap:101 telephone-event/8000
> >
> 
>   That's all you need to know.  They are configured for RFC2833 and
> they're sending RFC2833.

I appreciate this is a 'how long is a piece of string question Kristian,
but is there likely to be a way I can fix this?