hi：if you are using PRI(Dahdi) to make a incoming calls. the error looks like this:
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All incoming DTMF tones over my DAHDI interface (a PRI) cause the following error:[May 16 08:38:27] WARNING[2387]: chan_dahdi.c:5624 dahdi_write: Cannot handle frames in 2 format[May 16 08:38:27] WARNING[2387]: file.c:723 ast_readaudio_callback: Failed to write frame -- Hungup 'DAHDI/1-1'
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the error is reported from digium, please refer this link to get more details:
https://issues.asterisk.org/view.php?id=15129
