Notification Equipment Synchronization: To avoid confusion for the duration of an unexpected emergency, NFPA 72 stipulates that notification appliances in the same space should be synchronized to produce a dependable and intelligible notify signal. A fire alarm panel might be guiding a doorway, providing the doorway is not really locked https://www.firesense.co.uk/type/conventional-fire-system/conventional-fire-alarm-control-panels/