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<p class=MsoNormal><span lang=EN-US>Hello.<o:p></o:p></span></p>
<p class=MsoNormal><span lang=EN-US>Does anyone remember the idea behind DSP_DIGITMODE_MUTECONF
option? <o:p></o:p></span></p>
<p class=MsoNormal><span lang=EN-US>I stuck at it while trying to nail down
problems with Zap channels muted for some reason. Although DSP_DIGITMODE_MUTECONF
probably is not related to my problems at the end, I spent some time looking at
the code and got some questions. First of all it looks like that code may be
outdated and does not perform any real job now. If it does, things are a bit worse
because if my understanding is right – the code is broken.<o:p></o:p></span></p>
<p class=MsoNormal><span lang=EN-US><o:p> </o:p></span></p>
<p class=MsoNormal><span lang=EN-US>In short it looks like the code does some simple
de-bouncing for DTMF digits and sends AST_FRAME_DTMF with subclass ‘m’
(MUTE) before first digit and AST_FRAME_DTMF with subclass ‘u’ (UNMUTE)
after the last.<o:p></o:p></span></p>
<p class=MsoListParagraph style='text-indent:-18.0pt;mso-list:l1 level1 lfo1'><![if !supportLists]><span
lang=EN-US><span style='mso-list:Ignore'>1.<span style='font:7.0pt "Times New Roman"'>
</span></span></span><![endif]><span lang=EN-US>I’m not really sure why
this is needed at all because AFAIK digit-detection code in the dtmf_detect removes
DTMF tones when it finds digits anyway (unless NOQUELCH flag is passed)<o:p></o:p></span></p>
<p class=MsoListParagraph style='text-indent:-18.0pt;mso-list:l1 level1 lfo1'><![if !supportLists]><span
lang=EN-US><span style='mso-list:Ignore'>2.<span style='font:7.0pt "Times New Roman"'>
</span></span></span><![endif]><span lang=EN-US>dtmf_detect also does
de-bouncing.<o:p></o:p></span></p>
<p class=MsoListParagraph style='text-indent:-18.0pt;mso-list:l1 level1 lfo1'><![if !supportLists]><span
lang=EN-US><span style='mso-list:Ignore'>3.<span style='font:7.0pt "Times New Roman"'>
</span></span></span><![endif]><span lang=EN-US>I do not understand for what reason
app_queue.c sets CONFMUTE option on Zap channels (using ast_channel_setoption( …
AST_OPTION_TONE_VERIFY…)<o:p></o:p></span></p>
<p class=MsoListParagraph style='text-indent:-18.0pt;mso-list:l1 level1 lfo1'><![if !supportLists]><span
lang=EN-US><span style='mso-list:Ignore'>4.<span style='font:7.0pt "Times New Roman"'>
</span></span></span><![endif]><span lang=EN-US>Chan_zap seems to be the one
real user for ‘m’/‘u’ frames but I’m nit sure
what it does with them.<o:p></o:p></span></p>
<p class=MsoNormal><span lang=EN-US><o:p> </o:p></span></p>
<p class=MsoNormal><span lang=EN-US>I’ll appreciate if someone could shed
some light on the DSP_DIGITMODE_MUTECONF / AST_OPTION_TONE_VERIFY stuff.<o:p></o:p></span></p>
<p class=MsoNormal><span lang=EN-US><o:p> </o:p></span></p>
<p class=MsoNormal><span lang=EN-US>Thanks.<o:p></o:p></span></p>
<p class=MsoNormal><span lang=EN-US><o:p> </o:p></span></p>
<p class=MsoNormal><span lang=EN-US>PS: why I consider implementation broken: <o:p></o:p></span></p>
<p class=MsoNormal><span lang=EN-US>(note that I got these items only observing
the code, not under real tests)<o:p></o:p></span></p>
<p class=MsoListParagraph style='text-indent:-18.0pt;mso-list:l0 level1 lfo2'><![if !supportLists]><span
lang=EN-US><span style='mso-list:Ignore'>1.<span style='font:7.0pt "Times New Roman"'>
</span></span></span><![endif]><span lang=EN-US>While __ast_dsp_digitdetect
returns the same digit, the code will be generating AST_FRAME_DTMF_BEGIN frames
for that digit over and over <o:p></o:p></span></p>
<p class=MsoListParagraph style='text-indent:-18.0pt;mso-list:l0 level1 lfo2'><![if !supportLists]><span
lang=EN-US><span style='mso-list:Ignore'>2.<span style='font:7.0pt "Times New Roman"'>
</span></span></span><![endif]><span lang=EN-US>When digit changes without
going thru 0 (for example ‘5’ changes to ‘4’ without a inter-digit
interval), the code will be repeatedly generating AST_FRAME_DTMF_END only for
the first digit in sequence (because dsp->thinkdigit = digit; is missing)<o:p></o:p></span></p>
<p class=MsoListParagraph style='text-indent:-18.0pt;mso-list:l0 level1 lfo2'><![if !supportLists]><span
lang=EN-US><span style='mso-list:Ignore'>3.<span style='font:7.0pt "Times New Roman"'>
</span></span></span><![endif]><span lang=EN-US>It will never send ‘u’
(UNMUTE) frame because dsp->thinkdigit needs to be ‘x’ for that
while when the last digit was terminated (digit became 0), the dsp->thinkdigit
will be set to 0 and will never get ‘x’<o:p></o:p></span></p>
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