This one is something most people probably know. That being said if you're out of the car and need to put the back window up or down you can use the key. Turning left with the key in the tailgate lowers the window. Turning right on the key automatically locks the doors and puts up the window.
It should added that using the key is not automatic, like the button in the center counsel is. If you stop holding the key over, the window stops wherever is is at the time. That is true left or right....up or down.
P.S. A thread like this on the 4th Gen Forum from a few years ago turned out to be so informative that I still have the print out. Thanks for starting this one Model T !