This is not SCSI. There was a SCSI retrofit for the DSM-1 which allowed Mac formatted 20MB SCSI hard drives to be attached to store up to 10 systems apiece. If you find any let me know!

Now, HSI = High Speed Interface. One might notice it looks suspiciously like a Mac serial port. The promise was it would be a faster serial port than MIDI for transferring sounds, multisounds, programs, & combis to and from computers. I have asked Korg what the deal is and they said they could never get it to pass interference requirements in the states so it was never implemented. I intend to someday dig into the box and see if it works but is just covered up.