USB (Universal Serial Bus) is one of the newer all purpose technologies, which, is a "plug-and-play" interface between a computer and add-on devices (such as audio players, joysticks, keyboards, scanners, digital cameras, camcorders and printers).

The USB peripheral bus standard was developed by Compaq, IBM, DEC, Intel, Microsoft, NEC and Northern Telecom and the technology is available without charge for all computer and device vendors.

The biggest advantage of a USB is that a new device can be added to your laptop without having to add an adapter card or even having to turn the computer off. Serial ports and parallel ports transfer data at lower speeds. USB is much faster and also enables hot plug and play. What this means is that you can safely plug in or unplug devices when your computer is on. This is because these devices get their power through the USB connection itself within the PC. USB also makes installing devices simple. All you have to do is plug in the device and you are ready to go. You don’t have to open up the PC or add any card, fiddle with switches and settings to get it running. Another thing that is theoretically possible with USB is that you can add an unlimited number of devices. You would use a USB hub for this. USB ports operate at two speeds-1.5 Mbps and 12 Mbps, which depends upon the speed of the device attached to the port. USB uses the low-speed band while digital cameras and scanners use the high- speed channel.