Table 4. USB evolution
Type
Data Transfer Rate
Category
Introduction Year
USB 3.0/USB 3.1 Gen 2 5 Gbps
Super Speed
2010
USB 2.0
480 Mbps
High Speed
2000
USB 3.1 Gen 1 (SuperSpeed USB)
For years, the USB 2.0 has been firmly entrenched as the de facto interface standard in the PC world with about 6 billion devices sold, and
yet the need for more speed grows by ever faster computing hardware and ever greater bandwidth demands. The USB 3.1 Gen 1 finally has
the answer to the consumers' demands with a theoretically 10 times faster than its predecessor. In a nutshell, USB 3.1 Gen 1 features are as
follows:
•
Higher transfer rates (up to 5 Gbps)
•
Increased maximum bus power and increased device current draw to better accommodate power-hungry devices
•
New power management features
•
Full-duplex data transfers and support for new transfer types
•
Backward USB 2.0 compatibility
•
New connectors and cable
The topics below cover some of the most commonly asked questions regarding USB 3.1 Gen 1.
Speed
Currently, there are 3 speed modes defined by the latest USB 3.1 Gen 1 specification. They are Super-Speed, Hi-Speed and Full-Speed. The
new SuperSpeed mode has a transfer rate of 4.8Gbps. While the specification retains Hi-Speed, and Full-Speed USB mode, commonly
known as USB 2.0 and 1.1 respectively, the slower modes still operate at 480Mbps and 12Mbps respectively and are kept to maintain
backward compatibility.
USB 3.1 Gen 1 achieves the much higher performance by the technical changes below:
•
An additional physical bus that is added in parallel with the existing USB 2.0 bus (refer to the picture below).
•
USB 2.0 previously had four wires (power, ground, and a pair for differential data); USB 3.1 Gen 1 adds four more for two pairs of
differential signals (receive and transmit) for a combined total of eight connections in the connectors and cabling.
•
USB 3.1 Gen 1 utilizes the bidirectional data interface, rather than USB 2.0's half-duplex arrangement. This gives a 10-fold increase in
theoretical bandwidth.
Technology and components
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Summary of Contents for OptiPlex 5055 Tower
Page 1: ...Dell OptiPlex 5055 Tower Owner s Manual Regulatory Model D18M Regulatory Type D18M004 ...
Page 12: ...4 Lift the front bezel to remove it from the computer 12 Disassembly and reassembly ...
Page 44: ...b Slide and lift the system board away from the computer 2 44 Disassembly and reassembly ...
