Thanks for sharing what you’re learning. I checked with our ODL (OptoDataLink) senior developer, who said using PAC Sim shouldn’t make a difference when testing your ODL setup. (Of course, on your “real” application you don’t want to use the simulator since it’s only meant for testing and demo.)
The developer recommends against using Access at all, saying: “Access is the odd one out, it has all kinds of column names that don’t work, but it happily lets you create them (they are usually sql reserved words). … SQL Server Express is free, and it is a real database.” So that’s suggestion for today.