The KC64EXP is a multislot cartridge that allows to connect 2 cartridges to the expansion port.
You can enable cartridge in slot 1 or the one in slot 2 or even both of them together if they are compatible.
You can use the Swap I/O Lines feature to try to make work soma not compatible cartridges.
The data lines are fully buffered to “clean” data passing through in case of “noisy” c128.
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