[Asterisk-Users] sip.conf [general] dtmfmode=inband warning

[Mark Spencer]

> I have noticed when I add dtmfmode=inband under the [general] section
> in sip.conf I get flooded with warnings on the console after asterisk
> answers a sip call...
>
> WARNING[16401]: File dsp.c, Line 1106 (ast_dsp_process): Unable to
> detect process 2 frames
> WARNING[16401]: File dsp.c, Line 1106 (ast_dsp_process): Unable to
> detect process 2 frames
> WARNING[16401]: File dsp.c, Line 1106 (ast_dsp_process): Unable to
> detect process 2 frames
>
> This message repeats continuously until the call disconnects and it
> doesn't seem to recognize the inband dtmf.  What does this mean?

It means you can't use in-band DTMF and GSM together.  Since GSM provides
lossy compression, it is unlikely that in-band DTMF would be particularly
useful anyway.

mark