Several years back, the Vacu-Flush people were getting a lot of complaints about problems where the vacuum pump would run, off and on, all night long - keeping the occupants awake. They came up with a switch to shut off the vacuum pump when going to bed... (They've since improved their duckbill valves and vacuum switches, to stop that from happening. They also now have a much quieter vacuum pump. So the night switch, for the most part, is no longer necessary).
It was kind of like the old Henny Youngman joke about the guy going to the doctor. "Hey Doc, it hurts when I go like this!" Doc replies, "Well then, don't go like that! That'll be 50 dollars, please..."
If the pump runs all night long, here's a switch to shut it off at night...
They sold quite a few of them back in the '80's and '90's.