A remote keyless system (RKS), also known as remote keyless entry (RKE) or remote central locking, is an electronic lock that controls access to a building or vehicle by using an electronic remote control (activated by a handheld device or automatically by proximity). RKS largely and quickly superseded keyless entry, a budding technology that restrictively bound locking and locking functions to vehicle-mounted keypads.
Widely used in automobiles, an RKS performs the functions of a standard car key without physical contact. When within a few yards of the car, pressing a button on the remote can lock or unlock the doors, and may perform other functions.
A remote keyless system can include both remote keyless entry (RKE), which unlocks the doors, and remote keyless ignition (RKI), which starts the engine.
History
Remote keyless entry was patented in 1981 by Paul Lipschultz, who worked for Niemans (a supplier of security components to the car industry) and had developed a number of automotive security devices. His electrically actuated lock system could be controlled by using a handheld fob to stream infrared data. Patented in 1981 after successful submission in 1979, it worked using a "coded pulse signal generator and battery-powered infra-red radiation emitter." In some geographic areas, the system is called a PLIP system, or Plipper, after Lipschultz. Infrared technology was superseded in 1995 when a European frequency was standardised.
The remote keyless systems using a handheld transmitter first appeared on the French made Renault Fuego in 1982, and as an option on several American Motors vehicles in 1983, including the Renault Alliance. The feature gained its first widespread availability in the U.S. on several General Motors vehicles in 1989.
Prior to Remote Keyless Entry, a number of systems were introduced featuring Keyless Entry (i.e., not remote), including Ford's 1980 system introduced on the Ford Thunderbird, Mercury Cougar, Lincoln Continental Mark VI, and Lincoln Town Car, which Ford called Keyless Entry System (later renamed SecuriCode). The system used a keypad on the driver-side exterior door above the door handle. The keypad had five buttons that would unlock the driver's door when the code was entered, with subsequent code entries to unlock all doors, and the trunk. Nissan offered the same technology on the Nissan Maxima and Nissan Fairlady beginning in 1984, essentially using the same approach as Ford, with the addition of being able to roll the windows down and open the optional moonroof from outside the vehicle on the door handle installed keypad on both the driver's and front passengers door. The sixth generation Buick Electra featured a similar sill-mounted keypad for model years 1985-1988, superseded in 1989 by a remote keyless entry system.
Function
Keyless remotes contain a short-range radio transmitter, and must be within a certain range, usually 5–20 meters, of the car to work. When a button is pushed, it sends a coded signal by radio waves to a receiver unit in the car, which locks or unlocks the door. Most RKEs operate at a frequency of 315 MHz for North America-made cars and at 433.92 MHz for European, Japanese and Asian cars. Modern systems since the mid-1990s implement encryption as well as rotating entry codes to prevent car thieves from intercepting and spoofing the signal. Earlier systems used infrared instead of radio signals to unlock the vehicle, such as systems found on Mercedes-Benz, BMW and other manufacturers.
The system signals that it has either locked or unlocked the car usually through some fairly discreet combination of flashing vehicle lamps, a distinctive sound other than the horn, or some usage of the horn itself. A typical setup on cars is to have the horn or other sound chirp twice to signify that the car has been unlocked, and chirp once to indicate the car has been locked. For example, Toyota, Scion, and Lexus use a chirp system to signify the car being locked/unlocked. While two beeps means that driver's door is unlocked, four beeps means all doors are unlocked. One long beep is for the trunk or power tailgate. One short beep signifies that the car is locked and alarm is set.