Over the years, various engineering organizations have devised an almost silly number of different connectors for printers, scanners, and other peripherals (Figure 20-1 shows a typical assortment). The back panel—or front, or even side panel—of your PC may include any of these connector varieties.
Man, you gotta love USBs (Universal Serial Bus). The more of these jacks your PC has, the better.
The USB jack itself is a compact, thin, rectangular connector that’s easy to plug and unplug. It often provides power to the gadget, saving you one more cord and one more bit of clutter. And it’s hot-pluggable, so you don’t have to turn off the gadget (or the PC) before connecting or disconnecting it.