A value from the NortelNMIalarmProbableCause textual convention giving the probable cause of a particular alarm. Admins use this coded cause to quickly understand the likely root of the problem, such as a signal loss or configuration mismatch, without needing to interpret the free-text description alone. For example, a probable cause code corresponding to "loss of signal" would immediately point a technician toward checking the physical connection rather than software configuration.