Legacy Ports on a PC  When the PC was first designed, external
thingamajigs were attached to the console by using legacy ports
— specific and aptly named ports. If you wanted to attach a
keyboard, mouse, or printer, for example, you would use a
specific keyboard, mouse, or printer port. Since that time,
those older legacy ports have been phased out on PCs and
replaced by the USB port.  Some common legacy ports are defined
as follows:    • Mouse and keyboard: The mouse and keyboard
ports are designed specifically for what they do: The mouse
plugs into the mouse port, and the keyboard into the keyboard
port. And, despite the fact that both ports look alike, they’re
unique, and strange things happen when you connect things
improperly.    • Printer: It should be no surprise that the
computer’s printer can plug into the printer port. But you
probably didn’t know that the port was originally called the LPT
port. LPT was an IBM acronym for Line Printer. It may also be
called a PRN port.    • Serial: The original PC’