Connections in the back of the computer to connect printers, scanners, modem, mouse, keyboard, and any stuff. Things that are connected are called "Peripherals"

Characteristics:

1. Parallel Port - used for the printer as-well-as things like zip disks
2. Serial Port - used for modem
3. Keyboard and mouse connections are usually standard, are being replaced by USB connection
4. USB - universal Serial Bus - works with any devise that is compatible, mouse, modem, scanner, etc.
5. SCSI - Connect that is very high speed data rate, many devises including, scanners, printers, CD-ROMs, etc.
6. IE 1394 - Firewire - very high speed connection, similar to USB, mostly used for digital video.