Notification Appliance Synchronization: To prevent confusion during an emergency, NFPA 72 stipulates that notification appliances in precisely the same place should be synchronized to provide a steady and intelligible inform sign. Major highlights WARM PROMPT: The batteries are items. In the event the batteries are dead,pls obtain it by oneself. https://www.firesense.co.uk/type/conventional-fire-system/conventional-fire-alarm-control-panels/