Fire alarm systems consist of a Control Panel, Initiating Devices, and Notification Appliances.
The Fire Control Panel is the "brains" behind the fire alarm system. All of the system components are wired back to the control panel and programmed into the system. There are two main types of fire alarm control panels: Analog and Addressable. An Analog system has multiple initiating devices on one zone or area. (i.e. 7 Smoke Detectors in the Warehouse all report as one zone). An Addressable system means that each device in the system is an individual point. (i.e. 7 Smoke Detectors in the Warehouse with each one reporting as a specific point). Smaller systems many times are Analog because of their lower cost but sometimes local code requirement may mandate an Addressable system.
Initiating Devices consist of any device that notifies the main control panel of a fire alarm or trouble condition. These are smoke detectors, heat detectors, fire pull stations, sprinkler system activation valves, etc…
Notification Appliances are the devices that sound or light an area to notify people of a fire condition in the building. These are typically fire alarm horns, strobes or a combination horn/strobe.