How Does Keyless Entry Work for Vehicles?
Keyless entry devices are one of the conveniences that make the day flow a little smoother. Instead of having to fumble around for a car key, position it in the lock, turn the key, pull it out and then open the door, keyless devices merely require the push of a button to unlock the door. Also know as remote entry, these devices usually come in the form of a little plastic fob that fits on a key chain. It works by sending out a radio signal frequency that's picked up by a receiver device on the car. Both the fob and the car's receiver device are set to the same frequency, which is what keeps your fob from unlocking your neighbor's car doors. So in essence, a keyless entry device is a radio transmitter and the car is a receiver.
Radio waves, as versatile as they are, have become the cornerstone of technological advancement. Transmitter devices like keyless entry remotes rely on how these waves behave, and what they can do. How this works with a fob transmitter is the same process with any other electronic device. Radio transmissions travel in electromagnetic waves. What a fob device does is encode its message (the security code, and a lock or unlock command) onto an electromagnet wave. The fob contains a built-in antenna mechanism that transmits this wave to the car receiver's antenna. Both the fob and the receiver are configured to work on the same frequency level, which is what allows transmissions to get through.
Inside every keyless entry device resides a controller chip that acts as a coding device. As safety and security is a top priority in today's world, these chips use a fairly sophisticated coding method to ensure hackers can't mimic your car's entry code. Instead of transmitting the same code every time the device is used, the controller chip works off of a pseudo-random number generator that resets the entry code every time the fob is used. This system is based off of a 40-bit code algorithm able to generate any one of 1 trillion possible codes. Because the car's receiver is set to respond only to a specific code, it contains the same random number generator sequence as well. Both the fob transmitter and the car's receiver have memory locations that store each programmed code.
