This read-write EnvAlarmInputMode specifies how an environmental alarm input behaves: disabled raises no alarms, alarmopen raises an alarm when the dry contacts open, and alarmclosed raises one when they close. An admin cares because it must match the alarm logic to how the external sensor's dry contact is actually wired. For example, a door sensor wired to open its contacts when the door opens should have this set to alarmopen so the alarm fires exactly when the door is opened.