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SSA is a high-performance serial interface that is commonly used to connect peripheral devices like disk drives, optical disks, printers, and scanners to computer workstations and servers. It can handle up to two 20-MB/sec transmissions at the same time (in opposite directions) on a single port. A typical interface has two ports, so an SSA system has a total bandwidth of 80 MB/sec.

SSA was originally developed by IBM, but it was further developed by the ANSI (American National Standards Institute) subcommittee called X3T10.1. SSA is also specified as a physical layer serial interface in the SCSI-3 standard. Although SCSI designers have achieved high data rates with parallel SCSI, serial designs such as SSA are considered critical for high-data-rate performance and to boost cabling distances to devices.

An SSA connection consists of a shielded four-wire cable (two pairs). The distance between the host and a peripheral can be up to 25 meters (82 feet). At this writing, the longest SCSI cable distance was 25 meters (with 32 meters planned in the future). Devices can be configured in daisy-chain fashion or connected to switch boxes in a star configuration. A loop configuration is also available to provide a fault-tolerant cabling path that has no single point of failure.

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