...
It basically is an At Once Plus. It actually work very well except for the slow graphics, and no access to high density floppy (which were standard on PeeCee's even back in 286 days).
AFAIR, I could use HD floppies with the Vortex AtOnce 286 classic, as I had the registered Version of CrossDos 7 Gold installed...
But it could also be that I confuse it with using PcX on my A4000PPC Tower...my A500 time is too long ago...