This sets the interdigit timer used during digit collection once at least one digit is required to complete a match against the configured digit map, restarting after every new digit until the collected string matches at least one allowed pattern. This is specifically the still-searching-for-a-valid-pattern phase of digit collection, distinct from ccasGCnfShortTimer's already-matched-one-pattern-but-might-match-a-longer-one phase, so the two timers govern two different points in the same overall dialing sequence with potentially very different appropriate durations. If a digit map requires at least 4 digits to match any valid pattern, this timer keeps restarting after digits 1, 2, and 3, none of which alone match anything, until digit 4 arrives and produces a match.