Adaptec USBXchange User Guide - Page 2

User's Guide: USBXchange • 2 Introduction This user's guide explains how to use the USBXchange to allow SCSI devices to plug into the Universal Serial Bus (USB) port of your PC compatible or Apple Macintosh computer. The SCSI controller in the USBXchange allows you to connect up to seven SCSI devices to your desktop, portable PC, or Macintosh computer. These devices include fixed and removable drives, CD-R/W drives, DVD drives, hard disk drives, magneto-optical (MO) drives, and most scanners. The USBXchange provides transfer rates of up to 1.5 MBps or a maximum sustained rate of 700 KBps. Overview The USBXchange is designed as an integrated adapter with a 50-pin highdensity (SCSI-2) connector. For installation, you simply connect the male HD50 SCSI end of the USBXchange to the female HD50 SCSI connector on your SCSI device. See Installing the USBXchange on PC Compatibles on page 5, or Installing the USBXchange on a Macintosh on page 15 for more information. HD50 SCSI connector USB connector USBXchange HD50 SCSI-2 Connector The USBXchange is designed to act as a self-powered device and receives its power from either the termination power line of attached SCSI devices or, if not present, from the USB bus. In some cases, especially when using unpowered USB hubs with attached SCSI devices which do not supply SCSI termination power, the USB bus cannot supply the needed power for the USBXchange to operate. In these cases, you may need an external DC power source. See USBXchange Power Supply on page 13 (PC) and USBXchange Power Supply on page 20 (Mac) for more information.