For the record, FDX requires pilots who do not take a scheduled DH to check in twice via computer or phone for trips that start with a DH before a operational leg. The first time is within 48 hours of their scheduled show time (for the DH as scheduled), the second time is after arriving on station and confirming they are within 100 miles of said location. They must do the final check in within 8 hours of show time for a domestic flight or 12 hours if the operating flying is international.
If you commute into your base to operate a trip originating from such you only need to check in at show time, like a local bubba.
There is more, but it relates to online commuting into a same duty flight and stuff about being in position to rest before operating long flight segments.