The Microsoft USB 2.0 driver may not be listed as an available update if third-party USB 2.0 drivers are installed on your computer. You may have to remove the third-party USB 2.0 drivers, and then install the Microsoft USB 2.0 driver from the Microsoft Update Web site.
The USB 2.0 drivers for Windows XP that are on Microsoft Update today only recognize devices using the NEC USB 2.0 EHCI controller chipset. The industry specification for Hi-Speed USB is called the Enhanced Host Controller Interface (EHCI ). That doesn't mean you have to buy an NEC-brand controller. The NEC chipset is fairly ubiquitous in the USB 2.0 world. That chipset is also the first one to be certified by the independent USB 2.0 testing body. Although the USB 2.0 drivers currently available on Microsoft Update only support the NEC controller, there should be an update soon that supports all EHCI-compliant controllers.
If you've made sure that everything on your computer is USB 2.0-compliant, and you're still getting low-speed results, you may not have the right drivers. Symptoms in Windows XP can include error messages such as “The Generic USB Hub is a HI-SPEED USB device and will function at reduced speed when plugged into a non-HI-SPEED port,” or “A HI-SPEED USB device is plugged into a non-HI-SPEED USB hub.” You may also see your high-speed controller card tagged with a yellow exclamation icon in Device Manager. The problem is that although you have a Hi-Speed hub or controller, Windows XP doesn't recognize it.
Universal Serial Bus 2.0 support in Windows XP
You may experience any of the following symptoms:
- • Your Hi-Speed Universal Serial Bus (USB) 2.0 device does not operate in Hi-Speed mode.
- • If you plug in a Hi-Speed USB 2.0 device, you receive any of the following warnings:
- The Generic USB Hub is a HI-SPEED USB device and will function at reduced speed when plugged into a non-HI-SPEED port.
- HI-SPEED USB Device Plugged into non-HI-SPEED USB Hub. A HI-SPEED USB device is plugged into a non-HI-SPEED USB hub.
- • An Enhanced Host Controller Interface-compliant (EHCI-compliant) USB host controller appears in Device Manager with an exclamation point in a yellow circle, or with status code 28.