Does anyone know if HDI-20 and HDI-30 are compatible? I have a PowerBook 520c that has HDI-30, and want to get an external floppy drive, but the nice small external drives are all HDI-20 (they were made for the Duo line). Thanks!
I do not believe they are. That HDI-30 port is for SCSI transfers and requires a connector like the one in the photo to connect to a DB25 pin SCSI cable. EveryMac.com states there is no external floppy option for this model.
There was an option for swap-able PCMCIA card cage that opened other options like modems/ hard-drives / etc, but these are hard to locate (rare finds) and purchase. Sorry.