About Remote Keyless Car Entry

Switch your engine on, lock your doors, or open the truck from a distance. Remote keyless car entry is something like using a television's remote control. Most remote keyless car entry devices in America broadcast radio waves on a 315 MHz frequency. Europeans use a higher radio frequency than America and Japan. Flashing lights or the sounding of a horn are common features in remote car entry systems. Using a remote system is as easy as turning on a light or switching channels on a television remote. The remote control box that is worn on a keychain is commonly referred to as a fob.

History

The earliest remote keyless transmitters were tiny radio control boxes that used a simple signal. The problem with this early predecessor was that they all shared a universal signal. This meant that the earlier remote controls, primarily used for garage doors, left private property vulnerable to nearby signals from other remote control devices. The dip switch came along in the 1970's, but only had a limited level of security; roughly two hundred and fifty combinations. The concept behind the dip switch was synchronizing the control box in a garage with the remote control. This was done by wiring eight switches on the remote circuit board and eight switches on the control box to be identical.
General Motors was the first car company to feature a remote keyless ignition system in their product line.

Function

The remote control functions to lock and unlock car doors, open a car trunk, roll down the windows, and arm or disarm a car alarm. The interface that controls these functions is displayed on the face of the remote control or key handle. Some keyless entry units have special functions that operate by using a combination of the controls on the face of the remote, such as holding down the unlock button for a couple of seconds to roll down the windows. A common feature is the kill switch or panic button. The function of this button is to stop an accidental sounding of the car alarm. Usually, the car ignition will not start right after disarming the alarm.

Types

The keyless entry system is implemented into the key, or is attached to the keychain as a separate remote control. A remote entry device works by sending signals from the remote control, in the form of radio frequency, to the receiving system in the car. These signals are received in small pulses by the car system, and then interpreted to perform a task like unlocking a door, rolling down a window, popping the truck, or securing the locks on all doors. Some systems for keyless car entry are encrypted. Encryption prevents burglars from hacking your car system. This is an important function for remote keyless entry, especially for systems that allow for remote ignition to start a vehicle's engine running. All remote keyless car entry devices function as miniature radio transmitters. When you press a button, the transmitter switches on and transmits a radio code to your car.

Benefits

Never forget to lock a car door. With remote keyless car entry devices people can lock their cars from a distance, which can be a real time saver at the supermarket or any other public place. If you've ever had the experience of not being sure whether or not you looked your car doors, you'll understand the benefits of having a remote control for your car doors. Another common feature that benefits remote keyless car entry device owners is the ability to open a trunk with the push of a button on your keychain. This type of feature makes it easy to bring groceries to the car without having to put things down to unlock and lift the trunk of your car.

Considerations

Radio scanners are still a problem for anyone opening their car with a radio transmitter device, such as the ones used to open car doors at a crowded public place. A clever thief can capture the signal you send to your vehicle when you unlock your car door with a remote keyless car entry device. Still, it is more difficult for thieves to access your car remotely, because today's transmitters use a hopping code with over one trillion possible combinations. For more security, these remote keyless devices send a second signal to the car's receiver to store a new code. This way, the code is not the same code, and therefore the thief will have greater difficulty getting the code to access your vehicle. The real consideration here is what happens when you need to find your car after attending an all day shopping rampage, or you end up forgetting where you parked your car before you left it at the football game. Most people will press the remote button to signal the car to beep or light up the head lights. This acts as a beacon for locating your car, but it can also desynchronize your remote if you were to press the button a couple of hundred times in a very large parking lot. This problem might be solved by turning on your car engine, once you find the car, about eight times to set the receiver to program mode. Pressing the control buttons on the remote will signal the receiver to synchronize with your remote. When you're done, switch the engine off, and your remote is synchronized again.

Resources

• Keyless entry remotes