Transponder keys may also be called "chip keys". Transponder keys are automotive ignition keys with signal-emitting circuits built inside.

When the key is turned in the ignition cylinder, the car's computer transmits a radio signal to the transponder circuit. The circuit has no battery; it is energized by the radio signal itself.

The circuit typically has a computer chip that is programmed to respond by sending a coded signal back to the car's computer. If the circuit does not respond or if the code is incorrect, the engine will not start.

Many cars immobilize if the wrong key is used by intruders. Chip Keys successfully protect cars from theft in two ways: forcing the ignition cylinder won't start the car, and the keys are difficult to duplicate. This is why chip keys are popular in modern cars and help decrease car theft.

Transponder checking unit

Transponder is used in almost all keys of current generation vehicles. It is planned that transponders will be used in TWO Wheerler keys as well in near future. We have delivered more than 20 solutions where transponder verification is required.

Many modern automobiles have keys with transponders hidden inside the plastic head of the key. The user of the car may not even be aware that the transponder is there, because there are no buttons to press. When a key is inserted into the ignition lock cylinder and turned, the car's computer sends a radio signal to the transponder. Unless the transponder replies with a valid code, the computer will not allow the engine to be started. Transponder keys have no battery; they are energized by the radio signal itself

• TI and NXP transponder checking units
• FOB verification
• Manufacturer verification