IBM Gaithersburg (Md) complex uses the RR-9 system on all lighting. I ended up with a big box of the used relays and some switches because they always put new ones in on a remodel. There are 2 versions of the switch. The one with the larger rockers were more prone to sticking and burning out the coil. I probably still have some and my old house in Maryland has a bunch installed.
Ouch. That would make me not want to use their switches. But the system should work on normal two-throw momentary contact switches, right?
