English: Internal design of the IBM PS/2 Model 70, showing a 32-bit Micro-Channel Architecture SCSI controller plugged in next to a 16-bit MCA slot.

The top of the card has a 50-pin card-edge connector that is a standard SCSI connector. (I bought an edge connector that fit it to make a special SCSI adapter cable.) The card also has an external SCSI connector.

I do not know how the internal SCSI connector could be used, because PS/2 MCA systems do not provide separate internal power connectors for non-MCA hard drives. Power is instead normally supplied through the all-in-one MCA data/power card edge connector. Presumably some weird adapter would plug in to the MCA hard drive slot to bring out a standard drive power connector for a SCSI drive, but I've never seen such a thing so I have no idea.

Note also in the background, the standard 3.5-inch MCA hard drive and floppy drive plugged into the drive riser card. The model 70 could accommodate up to two floppy drives, though it is unclear why this is useful if you already have a hard drive. Installing second hard drive in the empty floppy bay was not possible. Meanwhile, the Model 70 could accept a 5.25-inch MCA hard drive but not a CD-ROM drive, which was still a hot new system accessory at the time.