asterisk users - Jun 2014 - Change time between DTMF

I already shortened the DTMF duration, but I need to change the time
elapsing between them.
The first thing I achieved by changing a parameter in asterisk.conf,
but how do I conquer the second goal?

You could use Timeout function. Like this:
1)Timeout(digit): max interval time between digits in DTMF.
2)Timeout(response): max time wait for autofallthrough.