USB 2.0 FAQ



How fast is USB 2.0?
USB 2.0 will be 480 Mb/sec, 40 times faster than USB 1.1.  With protocol and packet overhead, the maximum data throughput is approximately

How far away from a host can a peripheral be located?
The maximum cable length is 5 meters for a single cable and extending up to 30 meters, using 5 hubs. 

How many devices can be connected to one host?
You may connect up to 127 devices to a single host.

What's the status of Hi-Speed USB 2.0 in the marketplace?
Hi-Speed USB 2.0, the technology that extends the speed of the peripheral-to-PC connection up to 40 times over existing capabilities, is now market ready. In fact, dozens of Hi-Speed USB 2.0 products are now in the market in the U.S., Japan, and elsewhere. XP drivers are currently available from Microsoft. 98Se, ME, 2000 drivers are available from 3rd party vendors (Orange Micro and Adaptec). Expect to see USB 2.0 PCs shipping in Q3 2002 as Intel's 845 chipset hit the mass market with integrated USB 2.0 controllers.

What are the benefits of Hi-Speed USB 2.0?
The higher bandwidth of Hi-Speed USB 2.0 will support the most demanding PC user applications, such as digital image creation and web publishing, where multiple high-speed peripherals will be running simultaneously. Hi-Speed USB 2.0 is expected to replace USB 1.1, which is already a ubiquitous connector on PC systems today for such peripherals as keyboards, mice, joysticks, removable storage, printers and scanners.

When was the final USB 2.0 specification released?
The spec was released at WinHEC in April 2000.  

Who developed the USB 2.0 spec?
The USB 2.0 spec was developed by a team of seven industry-leading companies, collectively named the USB 2.0 Promoter Group. The group consists of Compaq, Hewlett Packard, Intel, Lucent, Microsoft, NEC, and Philips.

Since Hi-Speed USB 2.0 is now about the same speed as IEEE 1394a, don't they compete?
No. Hi-Speed USB 2.0 is expected to become ubiquitous on all PC platforms because it is more easily integrated into the core chipsets, at which time it will become the preferred connection for PC peripherals. IEEE 1394's primary target is audio/visual consumer electronic devices such as digital camcorders, digital VCRs, DVDs, and digital televisions. Therefore, the two connections will differ primarily in application focus.

What is USB On-the-Go?
The supplement to the USB 2.0 specification is expected to be available in early 2002. It is currently under development by a subcommittee authorized by the USB 2.0 Promoter Group, the original developers of the USB 2.0 specification.

Is Microsoft supporting Hi-Speed USB 2.0 in Windows XP?
Microsoft fully supports Hi-Speed USB 2.0, and has been working to develop driver support since its inception. Microsoft currently has production Windows XP drivers available and is expected to have Windows 2000 drivers available by the end of the year."

Which Intel P4 Motherboards support USB2.0?
Intel ICH4 Southbridge chipsets support built-in USB2.0 EHCI.  These are included on the 845G, 845GL and 845E chipset family. A list of current Intel motherboards can be found at:  http://developer.intel.com/design/motherbd/flex.htm

Will my PC today work with a Hi-Speed USB 2.0 peripheral product?
Assuming you have a PC that has USB 1.1 (which is most likely), if you plug your Hi-Speed USB 2.0 peripheral into the USB 1.1 system, your system will perform at the USB 1.1 speed. You will need to update your PC either by adding in a PCI add-in card or purchasing a new MB with a discrete host controller that supports Hi-Speed USB 2.0 and installing Hi-Speed USB 2.0 drivers.

Where can I get more info on Hi-Speed USB 2.0 in general?
The USB-IF has a website, it's www.usb.org.

What happens if I buy a Hi-Speed USB 2.0 product without the logo?
The product without the logo signifies that the product has not gone through compliance testing and you may not get the performance and/or quality that the USB-IF feels is part of a USB logo program.

If Hi-Speed USB 2.0 is 40X faster, why is it that a CD-R/W, for example, is only 6X faster?
The 40X speed improvement is specific to the bus. What this literally means, is that the bus is no longer the bottleneck in performance. The actual performance improvement for a given product is dependent on how fast that product can run. Over time, you should see product vendors improving their products to take advantage of the 40X bus.

I have a PC that runs Windows 98, can I still use Hi-Speed USB 2.0 products?
Yes, assuming first that you install a Hi-Speed USB 2.0 add-in card and you install a Hi-Speed USB 2.0 driver. Since Microsoft is only developing drivers for Windows XP and 2000, you will have to use a 3rd party vendor's drivers. In most cases, if you upgrade your PC with an add-in card, it will come with a Hi-Speed USB 2.0 driver install CD, that covers 98, 98SE, and ME.