SIM CARD: Requires a focused knowledge sim to the SMS messages,put it in the rear slot of the principle alarm box.can add 6 groups preset alarm contact number and 3 teams sms contact number The difference between an FACP and annunciator panel is the fact FACP is the leading control https://www.firesense.co.uk/type/conventional-fire-system/conventional-fire-alarm-control-panels/