[cisco-voip] Please help with DTMF Events Through SIP Signaling

[Jordan Schidlowsky]

Hi All,

We are having some problems transmitting DTMF tones from PSTN through to
our SIP proxy.  From what I understand we would like to implement it using
SUBSCRIBE/NOTIFY feature described in DTMF Events Through SIP Signaling
feature on the cisco.

Currectly we have two options.  Our current version of IOS does not
support cisco's proprietary DTMF-relay through SIP-notify.  We will either
be using dtmf-relay through rtp-nte (RFC 2833), or the SUBSCRIBE/NOTIFY
feature described in the SIP Signalling feature.

I would really like the get the SUBSCRIBE/NOTIFY feature working.  If
anyone has this working or has any knowledge it would be greatly
appreciated.  Right now when any SIP application trys to SUBSCRIBE to the
cisco we always receive a 481 Call Leg/Transaction does not exist.  The
documentation and examples on this issue are scarce and I'm having a hard
time finding info about it.  Is the SUBSCRIBE sent within a dialog or
outside a dialog?

Also is anyone sucessfully using out-of-band dtmf-relay using sip-notify? 
If this feature is working well we might consider upgrading IOS to a newer
version.  currently running 12.3(6)......

Once again ANY help or suggestions would be greatly appreciated.

Thanks all!
-Jordan