USB: The Future and the Past
With over 6 billion USB devices sold to date, the wildly-successful USB interface is the most common means to connect personal computers to peripheral devices such as keyboards, printers and mice. In its day, USB 2.0 offered more bandwidth than similar interfaces as well as the ability to provide electrical power to the peripheral devices it supports, eliminating the need for power converters and/or plugs. Fast and easy to use, USB has gained rapid adoption over the last two decades.
But by 2007, some weaknesses began to show. First, peripheral devices--such as high-capacity disk drives—were demanding more power than USB 2.0 could supply. Second, while USB 2.0 worked great for mice and keyboards, it couldn’t handle the bandwidth requirements for analog monitors. Third, the future bandwidth requirements for HD monitors and high-capacity disk drives meant that USB 2.0 was in danger of becoming obsolete for these applications.
So in November of 2008, the standards body that controls USB issued the new USB 3.0 standard. It provides a 10X improvement in data throughput, and devices built to the 3.0 standard have started shipping in the last few months. In technical terms, USB 2.0 was limited to a theoretical throughput of 480 megabits per second (with a practical limit of about 320 mbps), while USB 3.0 offers a theoretical throughput of 4.8 gigabits per second.
What does it mean?
First and most importantly, USB 2.0 isn’t going away any time soon. The very first USB 3.0 devices started shipping late this year, but they’re focused on the high-end niche products that require its additional capabilities. The installed base is very large and it works great in many applications. There’s no reason to rush to the new standard.
Furthermore, USB 3.0 is 100% backward compatible, so there’s no need to budget for replacement parts;
Lastly, USB 3.0 will only work if all three parts of the equation—host computer, connecting cable and peripheral device—are all USB 3.0 compatible. If any one of them is only USB 2.0 compliant, then you'll be limited to the lower standard.
USB 2.0 vs. 3.0: How can I tell?
Although the connectors will maintain the same form factors, USB 3.0 adds more internal contacts. Below are pictures of USB 2.0 and USB 3.0 interfaces.
Here are some USB 2.0 products you might be interested in:
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