Universal Serial BusWe know that all of the loyal Computer Tips readers are ever grateful for this series of tips, and you have probably all been wondering what you can do to thank us for all this information. Your first tip today is... Show When buying someone a gift, buy them something that they already have a lot of, because that is obviously something that they like. So if you were looking to buy us a gift, you would buy us computer hardware! Yes, there is no gadget that we would not love to have. You buy it, we'll try it out. Now, having said that, you would think that there would be some limit to how many "things" (which we computer people might call peripheral devices) we could actually connect to our computer. Historically, allocating the precious resources of your system unit to multiple peripheral devices has been a major problem. Probably the most onerous culprit in this endeavor has been trying to assign a unique IRQ (interrupt request line) to each device. The general rule has always been that each device had to have its own separate IRQ, Good news is here! No longer do we have to crawl around on the floor plugging and unplugging devices. No longer do we have to remove the cover of our computers to install and remove devices (although, admittedly, this is fun to do). No longer do we have to fight the IRQ battle. Universal Serial Bus (USB) is a relatively new external input/output interface that greatly enhances the portability of peripheral devices. USB devices are external to your actual system unit, so they are much more accessible than internal devices -- you need not remove the cover of your computer to install or remove a USB device. USB devices are Plug and Play, so setup and configuration is relatively easy. USB devices are even hot swappable, meaning that you shouldn't have to reboot your computer just because you have plugged in a new USB device. USB supports up to 127 devices (yes, up to 127 devices!), arranged in a tiered star topology (see the diagram to the right). Most new computers today come supplied with two USB ports. Additionally, many USB devices are equipped with one or more USB ports into which you can plug yet another USB device, daisy-chaining your USB devices one after another. In the diagram to the right, a USB-enabled keyboard (on the far right of the diagram) plugs into the host computer; the keyboard is equipped with a USB port, into which a digital camera can be plugged. Plugging your camera into your keyboard is certainly much more convenient than getting down onto the floor and crawling under your desk to find a port on the back of your computer! Thus, one of the nice features of USB is the ease with which you can connect devices physically. That is, your ports can be made to be easily accessible. You can purchase inexpensive multi-port USB hub devices which will support several USB devices. In the diagram, a 3-port hub is used (in Tier 1). A USB scanner, a USB CD-RW drive, and another hub are plugged into the 3-port hub. One of the biggest advantages of USB is that the entire chain of devices requires only a single IRQ from the host computer. With modern PCs suffering from an interrupt shortage, this is a major benefit, one which should spur the adoption of this interface for lower-speed devices. The availability of USB devices has grown through the past year to the point that USB should probably be a consideration for just about any peripheral device that you buy. Things to Know about USB
Please let us know if this tip has been helpful. Email to . Date posted: 03/13/00 Can connect up to 127 different peripherals together with a single connector?USB (Universal Serial Bus) is a newer type of serial connection that is much faster than the old serial ports. USB is also much smarter and more versatile since it allows the “daisy chaining” of up to 127 USB peripherals connected to one port.
What is used to connect a peripheral device and a computer together?Peripheral devices can be connected to your computer via USB port, serial port, parallel port, specialized network card, or Ethernet network. Local area networks (LANs) commonly use Ethernet networks for machine connection.
What is used to attach peripheral devices to the motherboard?port: A connection point that is used to attach a peripheral device to a motherboard. processor: See CPU.
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