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USB 3 – The Facts

usb3

USB 3.0 is the second major revision of the Universal Serial Bus (USB) standard for computer connectivity. The standard from 2008 implements a 5 Gbit/s transfer rate. In the late 1990s, the first major revision was made to the USB 1.1 specification. The revision was called USB 2.0 which added a new transfer speed called Hi-Speed (HS – 480 Mbit/s) to the earlier speeds (Low Speed (LS) – 1.5 Mbit/s and Full Speed (FS) – 12 Mbit/s).

The enhancements to Super Speed USB are not just for higher data rates, but for improving the interaction between device and host computer. While the core architectural elements are inherited from before, several changes were made to support the dual bus arrangement, and several more are notable for how users can experience the improvement that USB 3.0 makes over USB 2.0.

Major USB 3.0 improvements

  • Higher transfer rates (up to 4.8Gbps)
  • Increased maximum bus power
  • New power management features
  • Full-duplex data transfers
  • Support for new transfer types
  • Backward USB 2.0 compatibility
  • New connectors and cables

The good news is that USB 3.0 has been carefully planned from the start to peacefully co-exist with USB 2.0. First of all, while USB 3.0 specifies new physical connections and thus new cables to take advantage of the higher speed capability of the new protocol, the connector itself remains the same rectangular shape with the four USB 2.0 contacts in the exact same location as before. Five new connections to carry receive and transmitted data independently are present on USB 3.0 cables and only come into contact when mated with a proper Super Speed USB connection.

USB 3.0 achieves the much higher performance by way of a number of technical changes. Perhaps the most obvious change is an additional physical bus that is added in parallel with the existing USB 2.0 bus. This means that where USB 2.0 previously had 4 wires (power, ground, and a pair for differential data), USB 3.0 adds 4 more for two pairs of differential signals (receive and transmit) for a combined total of 8 connections in the connectors and cabling. These extra two pairs were necessary to support the Super Speed USB target bandwidth requirements, because the two wire differential signals of USB 2.0 were not enough.

The Cable circuit for USB3 shielded wire as follows

usb3a

Latest OS from Apple and Microsoft starts supporting USB3 with connector. Apple OSX Mountain Lion and Windows 8 comes with USB3 driver support.

Cool!!!

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December 12, 2012 - Posted by | Apple, DELL, Intel, Microsoft, USB Drive, Windows 8 | , ,

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