asterisk users - May 2010 - Delay on DTMF with SpeechBackground and Vestec

I have a delay of "0" on SpeecBackGround, but when I enter DTMF,
there's an
almost-exactly five second delay before it returns.  Where is this
delay controlled?  How can I shorten it?

Is there a way to set the maximum number of digits to look for?