In many of the more recent computers, little slot-like ports started to come included. Of course, the manual never said anything about the ports, and there were no devices back then with connectors that actually fit those slots. This slot is called a Universal Serial Bus (USB) port. Though this technology is fairly new, more and more manufacturers are beginning to sell USB-compatible peripherals and equipment. Almost 100 per cent of PC shipments are USB compatible, and the base of USB-installed PCs exceeds 500 million.

What the heck is USB?

USB stands for Universal Serial Bus. USB was developed by the computer industry leaders including Microsoft, Compaq, Intel, and NEC to increase the ease-of-use, performance and speed of peripherals by standardizing the way they attach to the PC. It is the easiest way to attach devices to your PC. The aim is on peripherals that connect to the outside of the computer. With USB, users won't have to open up the computer to install new peripherals. USB consists of a host, hub, and function. The host is the exchange point between USB peripherals, which is linked to a host controller, integrated into either the motherboard or PCI USB addon solutions. The hub allows multiple devices connect to the host. There is a USB hub already in USB-compatible compatible computers, that branches out to usually two connectors on the back of the computer. A function is a device that attached to the USB port.

So what? Why should I use USB?

  • Plug and Play(PnP) - USB was designed to meet to Microsoft's Plug-and-Play specification, meaning that devices can be plugged in, installed, and hot-swapped (removed and replaced with another device) without long installation procedures and reboots. That means devices will automatically detected as soon as you plug them in and will install without having to turn off the computer at all. Once you have a USB device's drivers installed, then you can remove it when you don't need it (even when the computer is on) and replace it when you do need it. Even better, you can even take it with you to other computers and connect it without installing permanent software, and after you are done using it, you can remove it without worry. No need for fiddling with the IRQ settings, no need to attach jumper cables. In fact, the best thing about USB is that it only requires one interrupt in the computer for all of the devices.

  • Hot Swapping and Multiple Device Support - Some people like to attach lots of devices to their computers at one time, but normally Windows can't handle it, and often people worry about their computers crashing or failing to work as they attach more and more devices to their PCs. The most often scenario is when a user has no place to plug in the device. USB gets rid of the problem by allowing up to 127 devices to be connected to it simultaneously. In order to connect more devices, however, you have to get a USB hub. Hubs allow multiple devices to plug into a single USB port. The reason you need one is to supply power to the additional ports and control the flow of information between the hub and the USB ports on the back of the computer. Still, with USB hubs you can attach and remove devices without restarting your computer.

  • High Speed and Electricity - USB ports have dual-speed transfer rates, 1.5 Megabits/second and 12 Megabits/second. Regular serial ports have a data transfer speed of only 230 kilobytes/second. It can also provide limited power, maximum 500mA of current, to devices attached to the USB bus. That means that most USB devices will not require a power supply like an AC adapter.

  • One size fits all - There is only one standard connection type for USB. There are two types of connectors, however. The series "A" connector is intended for all USB devices, is a plug for a peripheral and a socket for a PC platform. In most cases a USB cable should be captive (molded in) to it's peripheral. This saves connector cost, eliminates incompatibilities due to power drop in a cable and simplifies the user connection task. There are some cases where a captive cable is prohibitive. A very large heavy device may not be able to tolerate dangling cables that cannot be removed and some devices that are only occasionally connected, but have a useful function when not connected are good examples. The series "B" connector was created for such applications. The 2 connector series are different to prevent connections that violate the USB architecture topology.

What kind of peripherals can connect to USB?

There are thousands of USB peripherals on the market, from USB hubs, to scanners and printers, to digital video cameras. There are even USB modems and ISDN solutions on the market. Today, the USB logo appears all over the place, indicating peripherals that have USB support.