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Security Systems

Basic Description

car key and fobAutomotive security systems range from simple door locks and remote keyless entry systems to sophisticated systems that see, feel and hear possible intruders and actively defeat unauthorized attempts to enter or operate the vehicle. Layers of security recommended by the U.S. National Insurance Crime Bureau:

  • Warning Devices
  • Immobilizing Devices
  • Tracking Devices

Warning Devices: Most car security systems use the car's horn or a separate audible siren to alert everyone in the vicinity of an intrusion attempt. Some systems also flash the lights, play a recorded voice message or even call/text the vehicle owner's cell phone.

Immobilizer (Hot Wire Protection): Immobilizers are security device that disable the fuel, steering and/or ignition systems to prevent theft.

Vehicle Recovery (Tracking) (GPS/Radio Signal): Tracking systems help the owner to recover a stolen vehicle. Security systems with global positioning system (GPS) tracking can transmit a vehicle's current position by phone or over the web. RF tracking systems transmit a radio frequency signal that can be picked up by local receivers. These systems have an advantage in that they are effective even when a car is parked in a sheltered location that does not receive GPS signals.


Pressure sensors, switches, microphones, tilt sensors, vibration sensors, acceleration sensors, proximity sensors, GPS position sensor


Audible alarms, lights, RF link to telephone network

Data Communications
  • Communicates with immobilizer via 125 kHz carrier frequency. (RF)
  • Optional system communication via K-line, LIN, LS-CAN or HS-CAN
  • For RKE 315 MHz (United States and Japan) or 434/868 MHz (Europe)

AstroStart, Automate, Autopage, Avital, Black Widow, Bosch, Clifford, Commando, CompuStar, Crimestopper, Delphi, Denso, Fujitsu Ten, Hornet, LoJack, Python, ScyTek, Viper

For More Information
[1] Immobiliser, Wikipedia.
[2] How Car Alarms Work, Tom Harris,, Aug. 2, 2001.
[3] Vehicle Tracking System, Wikipedia.
[4] 2011 Toyota Sienna Engine Immobilizer How To by Toyota City, YouTube, July 26, 2011.