- ESDI ESDI=Enhanced Small Device Interface. Developed by Maxtor in the early 1980?s as an upgrade and improvement to the ST506 design.
- External SCSI D-Sub (Future Domain) Seems to be available on some Future Domain SCSI-controllers only.
- SCSI Centronics 50 pin (Differential) use RJ-21 (or RJ21) registered jack standard connector, also known as a 50-pin telco connector, or an Amphenol connector.
- SCSI Centronics 50 pin (Single-ended) use RJ-21 (or RJ21) registered jack standard connector, also known as a 50-pin telco connector, or an Amphenol connector.
- SCSI External IBM Burndy Special invention by IBM for use on IBM RS/6000 and IBM PS/2
- ST506/412 Developed by Seagate. Also known as MFM or RLL since these are the encoding methods used to store data. Seagate originally developed it to support their ST506 (5 MB) and ST412 (10 MB) drives.
- Adaptec RAIDport
- Novell and Procomp External SCSI This interface is nowadays considered obsolete.
- Paravision SX-1 External IDE Paravision was formerly Microbotics.
