The Apple IIGS is designed to be used with the vast majority of Apple IIe
hardware and software. However, there are some design differences that will
cause some products to be incompatible with the Apple IIGS.
Some CP/M cards designed for the Apple IIe use non-Apple conventions on the
I/O Select and Device Select lines in the expansion I/O slots. These cards
are not compatible with an Apple IIGS.
There are several CP/M card that work on the Apple IIGS. Please note, though,
that they MUST be run only when the Apple IIGS is in normal speed mode.
Manufacturer Card
Applied Engineering Z80
Advanced Logic Systems Z Engine
MicroSoft SoftCard
MicroSoft CATS
Digital Research any of the GoldCard series