Asterisk, and other worldly endeavours.

A blog by Leif Madsen

Issues: ast_rtp_senddigit_begin: Don’t know how to represent ‘f’ (one way audio)

I keep seeing questions like this recently on the mailing list and in the #asterisk IRC channel.

“ast_rtp_senddigit_begin: Don’t know how to represent ‘f’ shows up on the console then I get one way audio… *, wanpipe, zaptel, libpri 1.4.7…. any suggestions?”

I forget who originally said how to fix it (it was in a mailing list thread that I can’t find right now…), but basically the answer to resolve it was to disable the DTMF detection in the wanpipe driver. Seems it is picking up tones or artifacts in the audio path, and thinking a fax tone was detected. This is causing one way audio at random intervals.

Hope that helps someone!


Written by Leif Madsen

2009/07/18 at 10:18 am

Posted in Asterisk

Tagged with , , ,

One Response

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  1. From IRC:

    leifmadsen: setting TDMV_HW_DTMF = NO on wanpipe config gets rid of the one way audio and the following message on the cli… WARNING[9581]: rtp.c:2248 ast_rtp_senddigit_begin: Don’t know how to represent ‘f’

    So it seems you don’t necessarily need to recompile the wanpipe drivers if you’re having this issue. Just disable the option as mentioned above.

    Leif Madsen

    2009/07/19 at 3:47 pm

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