Small town (population <500) Church, three level residential elevator (according to the control box sticker & associated papers) circa 1992 installation, has a single momentary push button call button at each level, but also has a SPST key switch adjacent to the push button. Wiring is such that the key switch has to be "on" in order to put power to the push button contacts. My question is, why the key switch? All it effectively does is not allow the elevator to be called to that corresponding level.