I'm planning for several different methods for connecting the Floppy Emu board to the Mac. The board itself will be about 2 x 4 inches or a little smaller, so it should definitely fit inside an old external floppy drive enclosure.

The Floppy Emu board will have a male DB-19 connector as well as a male rectangular 20-pin IDC connector (the internal floppy connector on the motherboard). So you can:

1. Plug the board straight into the Mac's external DB19 floppy port. Then it will hang off the back like a dongle.

2. Use an Apple II Unidisk/DiskII DB19 to 20-pin IDC cable, like this one. These are still available from a few sources and on eBay. I ordered the one I linked, to confirm it works, but I'm 99% sure it will. Connect the DB19 end to the external floppy port, and the IDC end to the Floppy Emu board.

3. Use the DB19 to 20-pin IDC cable from an external Apple 3.5 inch floppy drive.

4. Unplug your internal floppy drive, and use the existing internal floppy cable to connect to the board's IDC connector. I'm not sure that cable is long enough to reach outside the case, though.

5. Same as above, but use a longer 20-pin IDC cable. You can use any generic IDC cable with straight-through wiring.