Originally Posted by Yflyer,Apr 19 2006, 05:26 AM

That is how I understood the write-up in the Helms manual -- they refer to it as fourth generation immobilizer and the previous setup as a second generation. I do not profess to be an expert on this by any means. However, my humble garage door opener does just that, the motor unit Rx/Tx sends a new code to the hand-held unit every time the door cycles.

Maybe someone else has more details.