Intel Universal Serial Bus (USB) Frequently Asked Questions (FAQ)
- How fast is SuperSpeed USB 3.0?
SuperSpeed USB 3.0 operates at 5 Gbps as compared to High-Speed USB 2.0, which operates at 480 Mbps.
- When was the final USB 3.0 specification released?
The spec was released in November 2008.
- Who developed USB 3.0?
USB 3.0 was developed by six industry-leading companies, collectively named the USB 3.0 Promoter Group: Hewlett-Packard, Intel, Microsoft, NEC (now known as Renesas Electronics), ST-NXP Wireless (now known as ST-Ericsson), and Texas Instruments.
- Does SuperSpeed USB 3.0 supersede High-Speed USB 2.0?
No, SuperSpeed USB 3.0 extends USB by adding a dual-simplex 5 Gbps capability that can be used by devices that need even higher performance than what is already available with High-Speed USB 2.0. SuperSpeed USB is complementary to High-Speed USB and most platforms are expected to support both SuperSpeed USB and High-Speed USB.
- Is there a difference between High-Speed USB and USB 2.0? Which is the correct nomenclature?
There is a difference in High-Speed USB and USB 2.0—the USB 2.0 specification covers 480 Mbps, 12 Mbps, and 1.5 Mbps speeds, while "High-Speed USB" refers to just the 480 Mbps portion of the USB 2.0 specification. We now use the term "USB" to refer to the 12Mbps and 1.5Mbps speeds.
- What is USB On-the-Go?
USB On-the-Go, available for High-Speed USB 2.0, addresses the growing need for mobile interconnectivity by allowing a USB peripheral to communicate directly with another USB peripheral. With the introduction of SuperSpeed USB 3.0, USB On-the-Go will soon be available for future mobile devices supporting 5 Gbps capability.
- What are the “SuperSpeed” and "High-Speed" logos, and what do they represent?
These logos are trademark-protected logos owned by the USB-IF for use by qualified licensees. The logos are a guarantee to the consumer that the product has undergone compliance testing for quality.
- Where can I get more information on USB and the logos I see on USB products?
USB-IF web site is the definitive source for all information pertaining to USB and the product certification program.
- How many devices can be connected to one host device?
Each host controller can support up to 127 devices. A host device may contain multiple host controllers.
- What if I have additional questions?
The USB-IF maintains a frequently asked questions web page.
- Are any technical books available that discuss USB?
USB Design by Example, Second Edition by John Hyde provides the expert knowledge and skills you need to design and implement a wide range of USB devices.