SCSI connectors connect devices that run small computer system interface standards and protocols. SCSI was developed for computer-based communications, usually communications between printers, scanners, hard drives, and disk drives. There is no standard connector size or pin count, but the most common is the ultra-small D form. This means that there is a protective metal shield around the male pin connector of the connector pair, which can align the connector in the proper direction while protecting the pins from damage. This ensures that the signal communication is correct and the pins will not be damaged due to incorrect alignment.
In most cases, SCSI female connectors are installed on certain types of circuit boards used in computers and peripherals. They use some form of cable connection, with SCSI male connectors on both ends of the cable. To connect the connectors, the male and female halves must be aligned correctly. Most connectors also have two screw fasteners to stabilize the electrical contact between the pins and the socket while providing structural support for the cable and connector connection.
From: https://www.dosinconn.com/introduction-scsi-connectors/
