[Freeswitch-users] Translating DTMF from RFC2833 to INFO

Metik freeswitch-users-list at metik.com
Sun Dec 6 11:16:43 PST 2009

Unless the IOS you are running is extremely buggy, "debug voip ccapi" 
commands should not provide you with that detail, what you really want 
to use is "debug voip rtp session named-event".

Normal SIP-to-PSTN calls should use both a pots and voip dial peer but  
DTMF relay type is determined by the voip dial peer.

I haven't ran into this issue (i.e. DTMF is ignored when using RFC 2833) 
previously in the wild.  Unlike some other SIP feature servers,  I have 
not had issues (with RFC 2833) between FS and Cisco IOS gateways.

Although unrelated to FS or any other SIP feature server, I have seen 
some issues when multple dtmf relay types are left enabled on a voip 
dial peer.  Also, there are some (older) IOS versions that have issues 
with DTMF duration which cause digits to be misinterpreted by the 
far-end (PSTN/POTS) but not ignored altogether. 


Yehavi Bourvine wrote:
> Hello Metik,
> 2009/12/6 Metik <freeswitch-users-list at metik.com 
> <mailto:freeswitch-users-list at metik.com>>
>     You previously stated that your Cisco gateway has some "bug" that
>     prevents you from using RFC2833, did you enable "dtmf-relay
>     rtp-nte" on
>     the voip dial-peer that the call is using?
> It is a PSTN dialpeer here, and it cannot be defined on it...
>     Unless you have configured the Cisco to support assymetric SDP or are
>     using a non-default "rtp payload-type nte" setting that does not agree
>     to well with FS's (default) "rfc2833-pt" setting, you should not
>     have to
>     use (SIP) INFO unless you want to.
>     I would recommend doing the following to ensure you are hitting the
>     correct dial-peer and it is configured for RFC 2833 ("rtp-nte"):
>     command: show dialplan number [number] | i (dtmf-relay|DTMF Relay)
> Unfortunately this does not work on PSTN dial peers.
>     Also, you can sift through "show sip-ua calls" for the call and ensure
>     that the value of "Negotiated Dtmf-relay" is "rtp-nte".
> This indeed shows that it has negotiated rtp-nte. Even when I do debug 
> for CCAPI events (I think) I see it decodes the DTMFs; however, it 
> ignores them while it accepts them via INFO. As I said: I guess this 
> is a bug.
> Since the gateway is on a remote site I hesitate on upgrading it until 
> I hae the chance to go there.
>                           Thanks, __Yehavi:
> ------------------------------------------------------------------------
> _______________________________________________
> 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

More information about the FreeSWITCH-users mailing list