Nobody seems to know this, not even the dealer...These keys are an all-in-one unit, and you insert it fully down into the cylinder until it locks, and the car starts automatically..Release the key from the switch and the car turns off.. My q is this: are these keys transponder-based like the old keys, or do they use infrared like the mercedes laser key..Looking at the key it appears to have an infrared window at the bottom of it, which gets activated and soon as the key is fully inserted into its "docking port" the key cylinder...