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Frequently Asked Questions
USB 2.0

Revision - 1.0

Q: How fast is USB 2.0?
A: USB 2.0 is designed to work at up to 480 mbps per second.

Q: Is USB 2.0 backwards compatible with version 1?
A: USB 2.0 is fully backward compatible with USB v. 1.1

Q: What are the differences between versions 1.1 and 2.0?
A: Version 1.1 supports two speeds, 1.5 and 12 mbps.  USB 2.0 supports 1.5, 12 (making it backward compatible), and 480 mbps.

USB 2.0 will likely not completely replace version 1.1.  I/O devices, such as keyboards, mice, and joysticks, have all the bandwidth they need in USB 1.1.

Q: How does USB 2.0 compare with FireWire?
A: Some say USB 2.0 will likely not replace FireWire (IEEE 1394/FireWire/I-link, etc.) because FireWire has established its place firmly within many industries, such as the camcorder industry.

Q: Will Microsoft support USB 2.0 in its 9.X systems?
A: Microsoft will not provide USB 2.0 support for the Windows 9x platform or Windows NT® 4.0.  3rd party vendors will make support available for operating systems other than Win 2000 and Win XP.

Q: What operating systems will it support?
A: Windows 2000, Windows XP and all future Microsoft operating systems.

Q: Is the drive stack between Windows 2000 and Windows XP different?
A: Yes.

Q: Then how will USB 2 work on Windows 2000?
A: “To support USB 2.0 on Windows 2000, a parallel (new) driver stack is needed. This driver stack will consist of Usbport.sys, Usbhub20.sys and Usbehci.sys. A host controller-specific coinstaller (Hccoin.dll) will also be provided to ensure proper Windows Update installation in the Windows 2000 scenario.”

Q: How do I ensure that my USB 2.0 devices work on Windows XP?
A: QFE 4 for HCT 10.0 includes tests to ensure that USB 2.0 Hi-Speed devices and USB EHCI host controllers work properly with Windows XP

Q: What makes USB 2.0 able to hold 480 Mbs?
A: USB 2.0 will specify a microframe, which will be 1/8th of
a 1msec frame. This will allow USB 2.0 devices to have small buffers even at high data rates.

Q: Who was involved in the development of USB 2.0?
A: Intel, Microsoft, Compaq, Hewlett-Packard, Lucent, Philips, and NEC were all involved in the development of USB 2.0.

Q: Are there any other names for USB 2.0?
A: USB 2.0 has been dubbed “USB Hi-Speed,” while USB 1.1 is now to be called “USB Basic Speed.”

Q: Will I have to get a new USB hub?
A: Yes.  You may use a USB 1.1 device in a USB 2.0 hub, but not the other way around.  If you plug a USB 1.1 into a USB 2.0 chain, all USB 2.0 devices will operate at 1.1 speeds.

Q: What is the maximum length of a USB 2.0 cord?
A: The maximum length is 16.4 feet.

Q: What do I need to upgrade my system to USB 2.0?
A: You will need a USB 2.0 host controller card, a USB 2.0 driver and an OS that supports USB 2.0.  It should cost from US$80 to $150.

Q: When will USB 2.0 be available for my laptop?
A: Laptop venders will not include 2.0 support for some time, although third party companies have already debuted USB 2.0 hardware for laptops.

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