How Fob Key Works
How Fob Key Works

How Fob Key Works

Fob key is a remote keyless entry system available on modern cars, it helps you locate your car easily especially in crowded parking lots and also reduce the risk of your car being stolen. A key fob will also help prevent others from capturing the code your key transmitter is sending (when someone has access to your code, they can easily re-transmit the codes to steal your car. The Key fob is a miniaturized and computerized key that works with a small chip that creates the codes that are transmitted while the small silver can is the transmitter on the key fob. 

The controller on the fob makes use of a hopping code to provide security. There are possible 1 trillion codes that can be programmed in your key fob, thanks to the controller chip. The controller chip in the transmitter has a wide memory that can hold 40-bit code, hence when you push a button on the key fob, it will automatically send the 40-bit code along with the function code that instructs the car what you want it to do (for instance it directs the car to lock or unlock the doors or open the trunk).

Functions of the receiver and transmitter in the key fob

Both the transmitter and receiver in your key fob rely on the same pseudo-number generator. The transmitter makes use of this random number generator to send 40-bit codes before it performs that requested function in your car. The code generated by the receiver is stored in the memory. When the receiver receives a valid code, on the other hand, it makes use of the same random number generator to pick a new random number. This means the transmitter and the receiver are synchronized but the receiver functions only when it receives codes it was expecting. 

If you are about a mile away and accidentally push the button on your key fob transmitter, the transmitter and receiver at this point will not be synchronized then the receiver will resolve this issue by accepting any from among the 256 possible codes from the random sequence and doing this means you can accidentally push the button on the key fob, up to 256 times before the receiver accepts the transmission but it wouldn't receive the transmission against on the 257th accidental push of the button. 

Contact Smart Locksmith for reprogramming and repair of the key fob

The synchronization of your key fob transmitter with the receiver can become problematic especially after prolonged usage, and that is the reason why you need to check your key fob for servicing from time to time to ensure it is working efficiently. Sometimes the button may fall off, and the inscriptions may even vanish, which can create confusion sometimes when you use the key fob, in which you may press the wrong button. Smart Locksmith has remained at the forefront of key gob programming and reprogramming over the years, we will surely help you out with all key fob issues. Give us a call today!

Feb 01,2019

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