Infrared AND Wireless - Why?

[@MARK]

My key fob is clearly wireless. Even when in my pocket the doors can be unlocked etc.

But on the drivers door handle and on the front of the key fob there appears to be an infra red window.

Why?

I have not seen any other car that has both. Wireless alone is normally sufficient for all uses so what gives?

 

[whitenemesis]

Fall-back should one system fail?

Also isn't DAS IR based?

Plus the IR close range operation allows the "summer opening/closing" function

 

[markjay]

My key fob is clearly wireless. Even when in my pocket the doors can be unlocked etc.

But on the drivers door handle and on the front of the key fob there appears to be an infra red window.

Why?

I have not seen any other car that has both. Wireless alone is normally sufficient for all uses so what gives?

I, too, fail to see the logic of it. Especially as the IR does not work very well on my car.

My guess is.... the RF fob can be pressed inadvertently while the car is not too far away. Which is not a problem, as the car will lock itself after a few minutes. The boot, of course, will not close itself, but then it only opens if you press the fob and hold it for a few seconds, so perhaps less of a chance of it happening. However a long press on the door lock on my previosu vauxhall Omega winded down all the windows.... this was a much more conveinet option thatn MB's point-and-shoot IR, but i am thinking that MB wanted to ensure that the windows can only be opened by themselves if you stand near the car and point the fob at the door.

Said that... I much preferred Vauxhall's press-and-hold keyfob for opening/closing of all the windows.

 

[@MARK]

fall-back should one system fail?

Also isn't das ir based?

das?

 

[whitenemesis]

DAS = Driver Authorisation System

How the key 'talks' to the ign to allow systems start.