Buttons
All the buttons on IBM stuff from the day had one element that tied them all together. It was the buttons. Every button on every piece of equipment was the same.
It was a rectangular piece of plastic, about one inch high by 1.5 inches wide by 1.5 inches deep. Near the back were a couple of cutouts that allowed the button to be held in it’s socket, yet if you grabbed it hard enough and pulled you could get it out.
All of the buttons had the stuff that worked in the socket. All the buttons stuck out from the surface the same distance. Some buttons were translucent and lit up because of a lamp in the socket. Some buttons were buttons and if you pressed them the socket would move. Some buttons were blank and there because you did not have the feature it would control, or they had 8 buttons and a full 3×3 grid looked far nicer than an almost grid, and 2×4 did not look good either.
Again, ALL the IBM equipment had these buttone, except this one.