So you're saying that an Apple /// disk image written out to a floppy on an Apple II isn't readable by an Apple ///? Why is that? You'd think an image written out to a floppy would be readable by the machine it's designed for, not by the machine that wrote the disk.

Hum, you might be on to something there. The cable I'm using is a DB25 to DB9 serial cable. Pretty sure it's straight through. I then have it connected to a DB9 to USB serial adapter on a Dell laptop. It works flawlessly on my IIe. I think you're right, the Apple /// needs a null modem cable.

I'll have to get my hands on one of those and report back.