When I posted the above JPG it came from an early R129 that has an IR remote.

I forgot to mention that when I had my 1989 R107 the car came with an aftermarket IR remote alarm that I really liked a lot , especially when the top was down.

I would exit the car, push the IR Remote and all the doors and compartments would lock and both windows would roll-up.

When I entered the car, I pushed the IR and it simply unlocked the doors and compartments but I had to lower the windows manually. BTW, this entire aftermarket system could be disabled by the simple flick of a hidden switch if necessary. It also had a system that sensed if anyone attempted to brake a window.

One of the features I currently like about my 2000 SL IR Door Locking System is if you are about 3-5" from the exterior IR driver door sensor and point and hold the door lock button it will raise the windows all the way up or to any position that you choose. Or you can leave them cracked on a hot day. Likewise you can roll the windows down while unlocking both doors but only in a close proximity. IR has it's limitation's in bright sunlight vs. a low lit garage. Sometimes it doesn't appear to work when in actuality the forces at be are interferring with the system.