The CPU (central processing unit)

This is the control panel. It is the metal box that contains the circuit boards (brains) of the system. The CPU receives instructions from the user through the keypad. It receives information about activity in the premise from the sensors. The CPU also communicates information about the premise to the monitoring station.

This is how the user talks to the CPU to tell the alarm system what to do. The keypad is used to turn the alarm on and off, It is also used to bypass zones and perform other programming functions.

The sensors are the parts of the system that detect events in the premise and report them to the CPU. They come in many different shapes and designs to detect numerous events. Examples of sensors include:

• magnetic contacts for doors and window
• motion sensors
• smoke detectors
• heat detectors
• glass break detectors
• cold temperature detectors
• panic pendants
• medic alerts

You should be sure to discuss what other options may be of benefit to ensure your system runs properly. These may include:

• backup battery
• local siren
• two way voice module

Alarm systems are available in hardwire or wireless. Hardwire systems simply mean that all the sensors are connected to the CPU by electrical wire. A wireless system uses transmitters and receivers to communicate via radio frequency between the sensors and the CPU. (there are no wires involved) Reliable and proven wireless technology does exist. Wireless systems can be used in areas where running wires is difficult or impossible.

They can also be used when people simply do not wish to drill holes and run wires in their premise. They are also common when installing a full perimeter system. (discussed later) Wireless equipment is more expensive due to the transmitters necessary with each sensor. However, installation costs are much less since no wires have to run to the sensors.