[cisco-voip] SIP Trunk question

[Eric Brander]

On Mon, Sep 27, 2010 at 2:53 PM, Jim McBurnett <jim at tgasolutions.com> wrote:
> So does anyone have a good idea as to why some calls on a SIP trunk will
> work fine with DTMF and a few fail?
>
>
>
> IE—
>
> Call to X – AA options don’t work..
>
> Call to Y—work fine..
>

I'm fighting with sometjhing similar right now in a configuration
between Cisco and NobleSystems (dialer platform based on Asterisk). If
the call placed from my Cisco desk phone communicates directly to a
call manager which then in turn passes the data across the SIP trunk
to Noble then everything works fine. Sometimes however the call will
be handled initially by the call manager but then the phone
communicates directly to the Noble SIP server instead of using the
call manager as an intermediary - when this happens it appears not all
commands are accepted, including DTMF. It seems load related - the
more SIP calls in-place, the more likely for this direct connection
problem.

I can't for the life of me find a solution... but not sure if its
related to your issue or not but sure sounds similar.