Adaptec USBXchange User Guide - Page 20

User's Guide: USBXchange • 20 USBXchange Power Supply The USBXchange 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 supply. Note: Adaptec strongly recommends that you plug the USBXchange directly into a USB port on your system. If you must connect through a USB hub, use only a self-powered USB hub. If your USBXchange is not supplied with enough power to operate, you will receive this error message: You can try either of the following to correct the problem: o Unplug the USBXchange and plug it directly into another USB port on your computer or into a self-powered hub that is connected to your computer. o Connect an external DC power supply to your USBXchange.