This object represents the timeout value for the critical
timer.
If used along with a digit map, the timer is started when
the last digit is received. i.e and when no more digits
are required for a digit map match. After this timer
expires, the digit map match is assumed to be complete.
If used without a digit map, the timer is started
immediately and cancelled (but not restarted) as soon
as a digit is entered.
This object is used by call processing when it processes
mid-call DTMF digit reporting.