For Hertz users, the CDPID file is created automatically when the Merge CDPID program or the Merge International CDPID programs is run. CDPID numbers assigned by Hertz are strictly numeric. For international operations that want to have their own private CDPID records (of which OKC is unaware), the CDPID number assigned must be alphanumeric.

The Electronic DRB program ignores alphanumeric CDPID numbers. (If it didn't, RA's with private CDPID numbers on them would error out on the EDRB transmission.)