One thing caught my eye. It is an electronic system for telling people if you are in or out. It must have been very technological at the time, and is still used. There is an electric box in the downstairs corridor with light that light up, depending on whether you have indicated you are in or not. It is shown in your own room, with a series of little light bulbs, and is changed by a simple connection system next to the door. It is wonderful!
There is also the older system next to the door of each room. You slide the pointer to show what you are up to, or where you are. Same thing a few decades later.