What are SCSI connectors?

By Amy Goetzman | December 06, 2022

Meet the Connector: SCSI Connectors

The Small Computer Systems Interface, or SCSI connector, (pronounced “scuzzy”) is a veteran of the small computing world. In the 1980s, this fast I/O connector served as a bus to link computers with components or peripherals such as disk drives. SCSI connectors typically feature two rows of pins in a robust, roughly D-shaped housing, although some variations organized the pins in shorter multiple rows. Early Macintosh personal computers utilized the SCSI for nearly every connection. While the rise of the USB and card edge connectors has led to the SCSI largely falling out of use in computing applications, current iterations are still used in some network applications.

The SCSI bus is controlled by a host controller, typically in the motherboard, or from a separate expansion card. SCSI uses three different signaling types: single-ended (SE), high-voltage differential (HVD), and low-voltage differential (LVD). Many versions of the SCSI connector have been used over the past three decades, most of which have become obsolete as smaller interfaces have evolved. Parallel SCSI connectors handle an 8, 16, or 32 bit wide bus running at 5, 10, or 20 megatransfers, with conventional or differential signaling. Today, these versions of SCSI have largely been replaced by Serial Attached SCSI (SAS), which includes three more transport types, each with one or more connector types. 24G SAS technology is widely integrated in modern data centers and storage applications.

Design Notes

Standardization: INCITS T10 Committee maintains the SCSI standard. The SCSI Trade Association promotes the use of the interface.

  • SCSI is a smart bus, controlled with a microprocessor, that enables up to 15 peripheral device connections to a computer. High-end single SCSI boards have two controllers and support up to 30 peripherals on a single expansion card.
  • SCSI enables several peripherals to connect to one host adapter, using only one slot in the bus.
  • In internal configurations, the SCSI cable was traditionally a ribbon or flat flexible cable. External configuration use standard cables.

Markets, Sectors, and Applications

  • Datacom/Telecom, Consumer
  • SCSI connectors are used in workstations, servers, and mainframes.
  • In older computing products, the SCSI is used to connect hard drives, scanners, printers, and other peripherals.


Hirose Electric, Molex, NorComp, 3M

Related Products:

  • SAS Connectors
  • USB
  • I/O connectors

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Amy Goetzman
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