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 difference being that 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 info on USB in general, and on the logos that 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 you with the expert knowledge and skills you need to design and implement a wide range of USB devices.