[asterisk-users] How to change outgoing DTMF frequencies on zaptel?

[Tilghman Lesher]

On Friday 20 November 2009 17:03:20 Zeeshan Zakaria wrote:
> Hi,
>
> I am having this issue that with one of the Asterisk servers, on zaptel
> hardware, that DTMF tones are 10-30 Hz too high than the upper limit for
> any DTMF digit frequency. This is causing problem with the equipment on the
> other end which is trying to recognize the DTMF digits. I tried different
> cards from the same vendor but it didn't help. For example for digit 1
> where it should generate 697 Hz, it would generate 712 Hz, and where it
> should generate 1209 Hz, it would generate 1230 Hz.
>
> Talking to the hardware support, they said it is not dependent on the
> hardware. I googled and found very little information, but apparently it
> was an issue with ztcfg and zaptel, but it was fixed more than a year ago.
>
> I found that in dsp.c file we could change the frequencies, but that is
> only for the incoming DTMF.
>
> Is there a way to change DTMF frequencies for the outgoing DTMF? If I could
> drop all the frequencies by 15 Hz, that might solve the problem which I am
> having.

It's hardcoded in tonezone.c.  Another possibility is that your phones are
generating tones that are out of whack with the standard, and Asterisk isn't
detecting them as tones because they're so out of whack and they're simply
getting passed, unchanged, onto the remote side, where they are similarly not
being detected.

-- 
Tilghman Lesher
Digium, Inc. | Senior Software Developer
twitter: Corydon76 | IRC: Corydon76-dig (Freenode)
Check us out at: www.digium.com & www.asterisk.org