[jclark003]

I would suspect you have a Charles industry C-power AB transfer switch. I do not believe they are in production but probably repairable. I just had my unit repaired as the control module went south so parts are out there. If that is what you have there should be a manual override too. Otherwise as Reel Magic suggested as long as you are only switching between two 50a/240v services I would think a household generator manual or automatic transfer switch would work. Have an electrician familiar wth ABYC standards do the install. Good luck.