Just WHAT IS THE UNIVERSAL SERIAL BUS?

The universal is one of the fast-growning and most widely accepted expansions to the personal computer in recent memory. It is impossible to buy an Intel_base PC(which make up 94% of the personal-computer market)with a Universal serial Port Bus. This is not say that The Bus is Limited to the computer world,not by ang strentch.Every computer hardware manufacturer is now acting to implement the Universal serial Bus on own platfrom.同行串行总线时进来对于个人计算机存储器扩展的，发展最快且得到广泛认可的一种总线。购买一台基于Intel芯片的PC(占个人计算机市场总额的94%)不能没有通用串行端口总线，这不是说UBS仅限于PC，这并不夸张，每个计算机硬件厂商都在他们的平台上采用了通用串行总线。why the sudden interest in something as seemingly trivial as a serial port? The answer is that the Universal serial bus is much more than a serial-port-it's a serial bus.this mean that a single port on the back of your computer can be the window,Groups of devices can be separated by concentration hardware called a hub,much as you would think of the Ethernet network.Fig 1-18 Illustrates what a typical network of the USB devices might look like.为什么突然之间对看似平常的穿行端口感兴趣呢？ 回答是通用穿行总线比穿行端口来，更贴近与一个串行总线，这表明计算机背后的这个端口是一个连向大容量设备的窗口（这句话并不是双关语气），这些端口以菊花链的形式连接到一起，各组设备可用称做总线的集中式硬件分隔开，这看待这种通用穿行总线时，最后将其看作是一种设备连成的网络，就像是以太网那样，图1-18形象的勾画了典型的USB设备网络。chaining a bunch of devices together might not seem like sunch a good thing at first glance,In fact,It might seem like a downright bad idea for a lot of devices to share what little bit of bandwidth serial devices have traditionally had to work with. After all. there is barely enough bandwidth on an RS-232 port to get a decent connection to a printer. The certainly isn't enough to talk to a digital camera  to download images.乍看起来把一串设备连起来不太好，实际上，对于大多数穿行设备要正常工作必须共享一点看待来讲，这明显是一个下策，毕竟，在Rs_232 端口上为正式连接的打印机的带宽几乎不够，更不用说下载数字相册了。The answer lies in providing a fast bus.we have to be careful with our terminology,though,because the universal serial bus is considered in the computer industry to be a 'mid-and-low-speed' bus,The Universal serial bus operates at over 10 million bits per second-this is the speed of the computer network in most businesses.问题在于提供一个快速总线，我们必须注意这一专业术语，虽然同行总线在工业中认为是一种中等偏下的总线，这种串行总线的运行速率可以达到10MB/s这是大多数计算机网络的速度。The Universal serial bus is not considered 'fast' when compared to things sunch as the fiber channel serial bus.which locks 

in at about 300 million bites per second.or to upcoming bus technologies sunch as the IEEE1394 ‘firewire’ bus to control audio and video sources that are ‘broadcast quality’. so we will accept that the usb is a ‘mid-speed’ bus and move on.
通用穿行总线比其他总线不能算作是快，比如光纤通道串行总线，其时钟速率为300MB/s。还有即将推出的如可控音频，视屏，达到广播级质量的IEEE1394’火线’总线技术等，因此我们认为USB是一种中速总线，并在继续向前发展。
The univesal serial bus was designed with the thought of providing pure digital audio,video,and telecommunications to the modern computer user,The speed of the bus is more sufficient to support thesr type of the devices.
通用串行总线的设计思想是现代计算机用户提供纯数字音频，视屏和远距离通信，该总线的速度足以支持这些设备。
A big problem with personal conputers has always connecting to the peripherals that you want to user,everything always seem to need its own adapter card plugged into the bus,There are video card for high resolution video,There are game cards to drive your joysticks ,There are sound cards to drive speekers amd there are video input cards to bring video into the computer. The lists goes on and on.
个人计算机的最大问题总是与你要使用外围涉笔的链接有关，任何设备似乎都需要将他们自己的适配器卡槽插入到该总线上，这些适配器卡包括高清晰度视频卡，驱动操作杆的游戏卡，驱动话筒的声卡以及把视屏输入到计算机的视频输入卡
Computers are shrinking,Everything year there are fewer slots for adapter cards.The goal of the personal computer industry truly is to make the computer as ubiquitous and unobtrusive as possible, at the same time ,the computer now contain sufficient technology and raw ‘horsepower’ to run the typed of the applications and drive the types of tasks that are requiring prtcion digital input and bandwidth intensive peripherials, vedio conferencing on personal computers is today a reality,surround sound stereo from your personal computer is a standard function.
计算机正在缩小，现在只有很少几个卡槽用于适配卡，个人计算机工业的真正目的是尽可能使用计算机普及和不引人注。同时，现在的计算机含有足够的技术和天然的马力去运行各种各样的应用程序和驱动要求精确的数字输入和带宽的各种类型的外围设备，用个人计算机举行视频会议今日已经成为现实，个人计算机的环绕立体声是一个标准功能，
The computer industry is striving to enclose a technology that is expanding to the point that mid and high speed digital peripheral devices are required into an ever shrinking footprint,this is where the universal serial bus comes into play.just put all the input and output to peripherals outside ‘the box’ and don’t use ang slots ,put the intelligence into the devices, rather than into the computer.
计算机工业正在努力去包含正在向中，高速外围设备推广的甚至成为设备缩小的一个象征技术，这就是通用串行总线起作用的地方，他真正的目标是将外围设备的输入和输出放在‘机箱’之外，不使用任何插槽，将智化功能放入这些外围设备中而不是放入计算机中，
peripherals designers are now freed up to implement solution that are in ‘one piece’ they don’t have to split the functionality of a peripheral between a devices and an interface card.This is a win for them,As this happens,the interal bus on your computer ceases to be saturated with traffic and information flowing between these interface cards.This is a win for you;you’ll find that you achieve better overall system performance with this type of configuration.
外围设备的设计师们这在从一体化中解脱出来，他们不必去对外围设备中的设备和接口卡功能进行分割，这是他们的胜利，在这种情况下，计算机内部总线不会因为这些卡之间的业务和信息流而处于饱和状态，这也是你的胜利，你会由于这种配置，会获得整个系统的更好性能。
Speaker designers are incorporating the functions perviously performed bu your sound card directly into the speaker. video input folks are building video digitizers to plug into the universal serial bus ,Even monitor manufacturers are putting Universal serial bus interfaces into the backs of their monitors.making the video vard obsolete,There are digital joysticks that offer super-high resolution.
扬声器的设计者们正在将声卡的功能直接放入扬声器中，视频输入设计者们正在把视频数字化功能放入通用穿行总线中，连显示器制造厂也在吧穿行总线接口放入其显示器的背板中，做成绝对的视频卡，另外还有提供超高分辨率的数字操作杆。
keyword
Universal serial bus (Usb)通用串行总线
platform 平台
serial port 串行端口
hub 集线器
download 下载
image 图像 印像 成像
fiber channel 光纤通道
video 视屏
telecommunication 远程通信 电信
adapter card 适配器卡
high resolution 高分辨率
joystick操作杆
game card 游戏卡
sound card 声卡
video conferencing 视频会议
surround sound stereo 环绕立体声
intelligence 智能
information　ｆｌｏｗ信息流
ｔｒａｆｉｃ　ｆｌｏｗ　业务流
ｃｏｎｆｉｇｕｒａｔｉｏｎ　配置
ｂｒｏａｄｃａｓｔ　ｑｕａｌｉｔｙ　广播级别