SCSI stands for Small Computer Systems Interface and was once one of the most popular ways to connect peripheral devices, such as scanners and printers to a computer. USB stands for Universal Serial Bus and nearly every peripheral can be connected to a computer using a USB port, from flash drives to mice and keyboards, making the SCSI obsolete. However, if you still have an old SCSI peripheral device you can connect it to your computer with a USB port as long as you have a SCSI to USB adaptor cable.
Turn on the SCSI peripheral device.
Plug the SCSI side of your SCSI to USB adaptor cable into the SCSI peripheral device.
Plug the USB cable into the USB side of the SCSI to USB adaptor cable.
Plug the USB cable into the USB port on the computer.
Install any software that may be needed to run the SCSI peripheral device, such as printer drives, and turn the SCSI device on.
Be sure to purchase a SCSI to USB cable with the compatible version of USB for your computer's USB ports.