I have a response to switch the aux 12v power to latched smoke
detectors attached to the Security Off response. After a smoke alarm
disarming the system does not reset the latches. However I can reset
them by setting to AWAY mode and disarming. Why?
S12V is normally on (supplying 12V) to smoke detectors and other similar types
The S12V is not reset when the system is disarmed, otherwise you would not be able to find out which detector out of others in the house which caused the alarm.
This S12V output can be pulsed off and on using an action when the system is armed to reset smoke detectors which are latched ie they may have an LED which turns on when the detector is activated and remains on until power is removed
