Dell P90F, Руководство по обслуживанию

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Technology and components
This chapter details the technology and components available in the system.
Topics:
• USB features
• Power button LED behavior
• HDMI 1.4
USB features
Universal Serial Bus, or USB, was introduced in 1996. It dramatically simplified the connection between host computers and
peripheral devices like mouses, keyboards, external drivers, and printers.
Table 1. USB evolution
Type Data Transfer Rate Category Introduction Year
USB 2.0 480 Mbps High Speed 2000
USB 3.2 Gen 1 5 Gbps Super-Speed 2010
USB 3.2 Gen 1 (Super-Speed 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 3.2 Gen 1 finally has the answer to the consumer's demands with a theoretically 10 times faster than its predecessor. In
a nutshell, USB 3.2 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 3.2 Gen 1.
Speed
Currently, there are 3 speed modes that are defined by the latest USB 3.2 Gen 1 specification. They are Super-Speed, Hi-Speed,
and Full-Speed. The new Super-Speed mode has a transfer rate of 4.8 Gbps. 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 480 Mbps and 12 Mbps
respectively and are kept to maintain backward compatibility.
USB 3.2 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 (see the figure below).
● USB 2.0 previously had four wires (power, ground, and a pair for differential data); USB 3.2 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.
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10 Technology and components