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The abbreviation of the USB is in English the Universal Serial Bus, Chinese meaning is "Universal Serial Bus (USB)". It is a new interface technology in the field of application in the PC. Since the 1995 PC with USB interface, USB interface gradually entered the 1998 large-scale practical stage. In recent years, with the popularity of a large amount of support USB PC, USB gradually become the standard of PC interface is the trend of The Times. On the host (host), a new PC almost 100% support USB; In peripherals (device), using USB interface equipment, such as digital camera, scanner, joysticks, tapes and floppy drive, imaging equipment, printer, keyboard, mouse and so on. USB device known as a large number of applications, mainly has the following advantages: 1, can be hot plug, farewell "parallel and serial interface to shutdown, the cable connected to, it is". 2, the system bus power supply, low power devices, without external power supply with low power consumption device, and can provide 5 v / 500 ma power. 3, support equipment is numerous, support a variety of devices, such as mouse, keyboard, printer, etc. 4, easy extension, can connect to multiple devices, up to 127. 5, high speed data transmission, the USB1.1 is 12 MB/s, USB2.0 is as high as 480 MB/s. 6 and convenient equipment interconnection, USB OTG supports point-to-point communication, such as digital cameras and printers, direct interconnection, without a PC. Of course, USB device also has its disadvantages, including: 1, power supply capacity, if peripherals when the power supply current is greater than 500 ma, the equipment must be the power converter. 2, transmission distance, USB bus line length of 5 m, even to expand with the HUB, as far as no more than 30 meters. |
