How Does A Key Fob Work?

Posted by Keyless Entry Remote on Sep 23rd 2014

They’re amazing little pieces of equipment, aren’t they? As they say, you can’t fully appreciate something until it’s gone. And, if you’ve had a keyless entry remote that’s stopped working, then you’ve likely severely missed the convenience that having one offers. Carrying a pile of groceries to the car? A keyless entry remote allows you to unlock your car without having to put the bags down. Need to pop open the trunk when your hands are all tied up? Push a button, and the trunk pops open!

Because these little devices are so convenient, we often don’t think about what makes them work. So, we figured we’d give a brief explanation of how keyless entry remotes work:

As you might have guessed, a keyless entry remote is basically a little radio transmitter. Inside of the key fob, you’ll find a tiny computer chip that’s attached to a radio transmitter. This transmitter then communicates with a receiver that’s located inside of your automobile.

So, how do the two communicate with one another, and what keeps a keyless entry remote from opening the doors of every car on the block?

Well, both the receiver and the transmitter make use of a security system. Both are programmed to transmit and expect a specific 40-bit code, which is then attached to a code that correlates to the action the car should take. So, when you push the “unlock” button on your key fob, the transmitter inside of the key fob sends the 40-bit code along with the unlock code to your car’s receiver. The car’s receiver then checks the code against it’s own: If they’re the same, it performs the function; if they’re different, then it does nothing.

Now, there’s one more bit of added security, too. Both the transmitter and receiver make use of a synchronized random number generator. This allows them both to constantly change the 40-bit code that ties them together. The purpose of this is to thwart hackers who might develop a way to break past the 40-bit code, and also to ensure that the key fob remains specifically tied to the car it works with.

So, as you can see, despite their tiny little size, keyless entry remotes are actually pretty complicated! If you’re having trouble with yours, or if you’ve lost or broken it, then take a look through our website and pick up a replacement key fob today!


Having trouble programming the remote or just want a professional to program the remote for you? Enter your city or zip code in the search box below to find a professional key fob installer in your area.

By Keyless Entry Remote Inc

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