This sets the debounce time, how long a raw line-signal state must persist before it is even considered for validation against the make/break timing objects, ccasILSMinMakeTime, MaxMakeTime, MinBreakTime, and MaxBreakTime, and per the MIB it must be set less than or equal to all four of those. Because it is a floor that all four ILS timing thresholds must exceed, this single object effectively sets the minimum granularity of signal detection for the entire incoming-line-signal table on this DS0, so raising it too high can make the debounce filter itself violate the constraint against those other timers. If this debounce timer is set to 20 ms, any of the four related ILS make/break timers configured below 20 ms would violate the MIB's consistency requirement and should be corrected together as a set.