Ultrasonic detectors can be prone to false alarms due to excessive air currents, and other extraneous ultrasonic noises. Infrared detectors . A device that is a passive sensor, because they do not transmit a signal for an intruder to disturb. They sense the radiation from a human body moving through the field of view of the detector. The type of control panel needed is dependent upon the overall intrusion alarm system.
Some control panels provide zoning capabilities for separate annunciation of the sensing devices.
These may also provide the low voltage electrical power for the sensing devices. Included in the control panel is the backup or standby power in the event of an electrical power failure. The success of the system relies on someone hearing or seeing the signal and calls the responsible authorities. The local alarm also serves to notify burglars that they have been detected. This may be advantageous in frightening off the intruder.