[asterisk-users] Asterisk and Cisco DTMF

[David Backeberg]

On Mon, Mar 1, 2010 at 9:25 AM, Szasz Szabolcs <szasz.szabolcs at gmail.com> wrote:
> Hi,
>
> I have encountered a DTMF issue. My scenario:
>
> Access carrier-----sip---->
> Asterisk-1.4.25.1-----sip---->CiscoGW-----ISDN----->TDM Switch
>
> the access carrier sends to Asterisk out of band (rfc2833) dtmf, Asterisk
> forwards it with SIP INFO method to Cisco gateway, but on TDM switch every
> digit is duplicated. Is it possible that the carrier sends inband along with
> rfc2833?

Possible? Sure.

Also possible that Cisco is passing along the in-band, as well as
converting the out-of-band to in-band, ergo two for one. You can also
tune the DTMF on the Cisco to ignore or set parameters on DTMF. Refer
to the IOS guide for the appropriate arguments.

Even worse, it's possible that you have a lot of echo, and the DTMF is
echo-y enough that it gets interpreted as two-for-one.

Can you take asterisk out of the loop, terminate sip carrier straight
into Cisco for testing?