The panel is the part of the system that decides what happens. Everything else reports to it, and everything the building does when a detector operates is programmed into it. Learning to read yours takes ten minutes and it is the single most useful ten minutes a responsible person can spend, because the panel will tell you what is wrong long before anyone else does.
What the panel is doing
It powers the detection circuits, watches them for alarm and for fault, holds the cause and effect programming that says which sounders operate and which plant shuts down when a given device activates, and maintains a standby supply so the system survives a mains failure. It also logs events, which is why the panel's own history is often the fastest way to settle an argument about when something happened.
Reading the display
Three states matter. Normal, where the only light on is the mains supply. Fault, usually a yellow indication with a zone or device address, meaning part of the system is not being watched. Alarm, meaning a device has operated. A panel sitting in fault is doing exactly what it is designed to do: telling you a part of the building is unprotected. Silencing the buzzer does not fix it and the fault stays recorded.
Repeater panels
A repeater mirrors the main panel somewhere else, typically at another entrance, so the system can be read from wherever people or the fire service actually arrive. Repeaters need their own zone plan beside them for the same reason the main panel does. If your fire service attends at a door with no panel and no repeater, that is worth raising with them rather than assuming somebody will run round the building.
Panel faults people cause
The three most common are a detector removed during building work and never disconnected at the panel, a battery past its service life so the standby supply fails its own test, and a device replaced with a different type that the panel was never reprogrammed for. All three show as a fault, all three are fixable, and all three are why an engineer's report that says fault found and cleared should also say what caused it.
Questions people ask about fire alarm control panel
Can I silence a fire alarm panel myself?
Trained staff normally can and should, using the panel key, once the cause is known. Silencing is not resetting, and resetting a panel before the cause is understood is how a real alarm gets treated as a nuisance.
What does a yellow fault light mean?
That some part of the system is not being monitored properly, for example an open circuit, a missing device or a failed standby supply. The panel should name the zone or address. It needs an engineer, not a reset.
How long should the standby battery last?
Long enough to run the system through a mains failure and still raise the alarm, which is a design figure for your system rather than a universal one. It is one of the things the periodic service is meant to test under load.