This specifies the External Alarm Input that will be monitored that will indicate loss of AC power. The enumerated set of values is system-dependent. For TA5000: External 1 = 1 External 2 = 2, External 3 = 3, External 4 = 4, External 5 = 5, External 6 = 6, External 7 = 7, External 8 = 8, External 9 = 9, External 10 = 10, External 11 = 11, External 12 = 12, External 13 = 13, External 14 = 14, External 15 = 15, External 16 = 16, External ACO = 17, Remote Server = 18 For OSP: External 1 = 1 External 2 = 2, External 3 = 3, External 4 = 4, External 5 = 5, External ACO = 6, Remote Server = 7 For TA3000 / HDX Systems: External 1 = 1 External 2 = 2, Remote = 3, External ACO = 4