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On Mon, 2005-05-23 at 17:04 -0400, Dan Evans wrote:
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<FONT COLOR="#000000">Asterisk has always "normalized" RFC2833 DTMF input. Initially, it sent </FONT>
<FONT COLOR="#000000">1 "DOWN" ("ON") followed by 3 "UP"s ("OFF"). I believe the 3 </FONT>
<FONT COLOR="#000000">terminating packets are recommended in the RFC. But having only 1 DOWN </FONT>
<FONT COLOR="#000000">meant that your DTMF would disappear if that one packet was dropped. </FONT>
<FONT COLOR="#000000">The UP's would just look like events associated with the previous keystroke.</FONT>
<FONT COLOR="#000000">The normaization was changed to 3 DOWN and 3 UP in patch 0003339 (sic), </FONT>
<FONT COLOR="#000000">to improve robustness.</FONT>
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Thanks Dan, <BR>
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I understand now why Asterisk is sending it three times (it really is redundancy), and I presume that most SIP ATA's are expected to handle the redundant packets correctly. My issue is that I have 3 ATA's from 3 different manufacturers, not re-creating the digit audio correctly, so I am wondering if there is some flaw in how Asterisk is creating these packets. I'll be doing more testing tonight.
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