วันจันทร์ที่ 15 กันยายน พ.ศ. 2551

USB Hubs and Ports Explained

USB standard has been the universal connection of external devices and equipment to the computer. The computers have two or four USB ports. Each of them can handle a large number of compounds, but adding more than two or four devices require a multi-connections. There are many types and this article tries to explain some important factors in selecting the best choice of the Centre for the system. USB-bus system for computers was introduced in 1996 and has undergone a number of additions and improvements. It began as USB 1, which was very slow and there were many mistakes. Version 1.1 has greater bandwidth 12 Mbit / second. The latest version 2.0 offers a broadband 480MBits/second and is fully compatible with USB 1.1 and 1. Link to a table showing the differences between the speed of USB (http://www.usb-products.com/usb-speed.aspx) Port Connections energy and
USB all take charge until to 127 connections (or devices) Computer Port. It is unlikely that this would be possible, given that the port can only supply 0.5 amps maximum. Some use a range of 0.5 amp, if they feed a power adapter from the network. Share bandwidth
generally the width of the port banda (http://www.usb-products.com/usb-port.aspx) is shared between all the devices that are connected via a hub. This means that if you want to add to the USB 2 with a USB 1.1 device, bandwidth is divided between the three devices. But there is an additional complications. Most centres (http://www.usb-products.com/usb-hub.aspx) on a single chip to control the bus. This means that the Centre will work with the smallest bandwidth determined by the devices connected to the USB-2 team that works well below the speed of transfer. Almost all USB hubs on the market today (passive and electricity) work like that. Many Chip centre
The transaction translator (TT) is the name of the chip control ancho de banda attached to each device connected. In schools that have a TT all devices have the same bandwidth and operates at the speed of the slowest. In the centres, with an HH per socket, which will each receive a portion of the width of the banda, but not limited to slower devices. Examples of such a centre is the centre of Belkin Tetra (http://www.usb-products.com/Products/Hi-Speed-USB-2-0-4-Port-TetraHub.aspx) It has 4 ports each among them their own TT. What it means in reality is that more TT centre will provide much latitude banda port, where a number of devices connected to a hub. The maximum performance and choice of place to connect a camera, if you are looking for maximum performance for each of its 2 USB devices, each device must be connected to a USB port on your computer. Other plug-in cards can make a large number of USB ports for most needs. But this situation may be going too far, except for most situations. Although a number of USB devices can be connected at the same time, it is unlikely that all will be in service. The commitment is useful to connect small devices bandwidth of a single centre. These include: mouse, keyboard, speakers, small appliances used. For products that require high bandwidth, and is often used in direct connection to a USB port is the best choice. The units include: Flash memory drives, external drives, webcams and other devices often. If you do not have enough ports of several ports to be added with a plug-in card, or a centre of good quality with several translators will be used. The devices placed in the middle are those used less frequently. These devices are placed directly into the port is used more often. Link to a pattern of range to assist in choosing a platform (http://www.usb-products.com/USB-Hub-Selection.aspx) Availability respect
What kind of configuration and combination, and port facilities will depend on the number of devices you want to join. Desktops, which usually finishes on the front of the box for easy access. These can be used by the devices are often connected / disconnected and require the highest ancho de banda. These units flash memory and external hard drives and portable MP3 players. USB have a tendency to root with cable connections and engine. These, of course, leaving the hearing, if possible, or behind the screen. For laptops, a small platform compact can be obtained. They may have its own wind or outside in cables ordered. Powered platforms and passive
centre May be limited for use in offline centres passive energy are based on the power of the USB bus. Powered centres have an adapter to give more power to devices. These devices vary in power they need. It is possible to run a series of devices to a single centre passive operating a USB port for as long as they have low energy consumption. With only 0.5 amp current that has only one of the devices which require the full power consumed in the centre replacement. Nothing serious will happen while the condition only that the degradation of many and all devices or disconnected from the machine. To avoid this situation, self-powered will be used. Nigel Stephens an online activity http://www.usb-products.com http://www.usb-products.com deliver the equipment. Nigel is the emphasis on providing useful information so that consumers can make informed choices.

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