A key fob is a small electronic device that gives access to physical objects such as cars and garages. In general, the term also refers to decorative items a person carries with their keys, like small trinkets or souvenirs. In the automotive industry, a key fob is a small device with buttons that unlock/lock the car’s doors.
Keyless entry systems mainly use key fobs for locking and unlocking doors. When a user pushes a button on a car’s key fob, a short-range radio transmitter in the fob sends a distinct coded signal to a receiver unit in the car. That as a result unlocks or locks the doors. In addition, some key fobs can also be used to open the drunk or to start the engine remotely.
A traditional key fob is an addition to the car key itself but the newer version of it has replaced the key altogether. This kind of fob is called a keyless fob. In addition to unlocking and locking the doors, a keyless fob is also used to start the engine.