usb中英文翻譯-文庫吧資料
2024-11-09 09:04本頁面
【正文】 is to buy an inexpensive USB hub. The USB standard supports up to 127 devices, and USB hubs are a part of the standard. 第 頁共 16 頁 5 A typical USB fourport hub accepts 4 A connections. A hub typically has four new ports, but may have many more. You plug the hub into your puter, and then plug your devices (or other hubs) into the hub. By chaining hubs together, you can build up dozens of available USB ports on a single puter. Hubs can be powered or unpowered. the USB standard allows for devices to draw their power from their USB connection. Obviously, a highpower device like a printer or scanner will have its own power supply, but lowpower devices like mice and digital cameras get their power from the bus in order to simplify them. The power (up to 500 milliamps at 5 volts) es from the puter. If you have lots of selfpowered devices (like printers and scanners), then your hub does not need to be powered none of the devices connecting to the hub needs additional power, so the puter can handle it. If you have lots of unpowered devices like mice and cameras, you probably need a powered hub. The hub has its own transformer and it supplies power to the bus so that the devices do not overload the puter39。s truly an amazing system! Anyone who has been around puters for more than two or three years knows the problem that the Universal Serial Bus is trying to solve in the past, connecting devices to puters has been a real headache! ? Printers connected to parallel printer ports, and most puters only came with one. Things like Zip drivers, which need a highspeed connection into the puter, would use the parallel port as well, often with limited success and not much speed. ? Modems used the serial port, but so did some printers and a variety of odd things like Palm Pilots and digital cameras. Most puters have at most two serial ports, and they are very slow in most cases. ? Devices that needed faster connections came with their own cards, which had to fit in a card slot inside the puter39。 第 頁共 16 頁 1 英文文獻(xiàn)原文 How USB Ports Work Just about any pute that you buy today es with one or more Universal Serial Bus connectors on the back. These USB connectors let you attach everything from mice to printers to your puter quickly and easily. The operating system supports USB as well, so the installation of the device drivers is quick and easy, too. Compared to other ways of connecting devices to your puter (including parallel ports, serial ports and special cards that you install inside the
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