SCSI Basics

SCSI, or small computer system interface, is an ANSI-defined type of industry-standard parallel interface for connecting peripheral devices to computers. Variations include SCSI-1, Fast SCSI, Plug and Play SCSI, Ultra SCSI, and Ultra2 SCSI. Termination is required at the two physical ends of every SCSI bus. Legacy SCSI-1, Fast SCSI, and Ultra SCSI devices are single-ended (SE) designs that use one wire per channel with a common ground. This approach assumes that the ground level is the same throughout a system, but often it is not. Newer products designed under the low-voltage differential (LVD) Ultra2 SCSI standard use two wires per channel for higher speeds with less noise. LVD Ultra2 SCSI products can also be connected over longer distances than SE designs. Back to SCSI Terminator page