This read-only object reports one of several specific unit-level hardware faults, from individual power-supply rail failures (+5V, +12V, -5V, +23V, -12V) through synthesizer lock failures (Tx, Rx 1st LO, Rx 2nd LO, reference PLL), an MPP50 IP module fault, and an EEPROM checksum error. As with cdd564UnitAlarm, each distinct value points a technician to a specific failing subsystem -- notably this CDM-570 version adds an MPP50 (IP Module) fault code not present on the CDD-564's version, reflecting the CDM-570's optional IP controller card, cdm570IPOption, as an additional failure point the CDD-564 doesn't have. A unit reporting the MPP50/IP Module fault code would direct a technician to investigate the optional IP controller card specifically, rather than the core modem's power supplies or synthesizers, since the fault is isolated to that add-on module.