On Tue, Mar 25, 2008 at 1:13 PM, John Lange <[EMAIL PROTECTED]> wrote: > BTW, if I remember correctly; the problem with Asterisk is that it > doesn't set the tone length (or it leaves it at zero or something). Some > systems consider this to be invalid so they ignore it but most systems > default to the bare minimum DTMF length. Either way this causes problems > since even the minimum length is very hard to detect reliably.
Ya, in Asterisk 1.2.x, there was no 'length' indicating how long the DTMF was held for (hence the 'variable length' in VLDTMF). Instead it would burst out 3 start DTMF frames, and 3 end DTMF frames (the reason for 3 of them on each was in case one of the frames was dropped since the frames are stateless, and thus do not get an ACK that they were delivered). This was the cause for some people getting duplicate and triplicate DTMF at the far end because each set of start/end DTMF frames were interpreted as individual key presses. VLDTMF largely eliminates this problem. > More recent versions of 1.4 have dramatically improved DTMF. Oh the struggles and joys I had debugging Asterisk DTMF until it improved to a usable fashion! -- Leif Madsen. http://www.leifmadsen.com http://www.oreilly.com/catalog/asterisk --------------------------------------------------------------------- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
