The back panel of your computer tower to which you connect peripherals is called the I/O board (see figure below). Items you find on your computer’s I/O panel may be labeled with text, or they may be indicated by certain icons.
The following list describes the components of a computer
Keyboard: The keyboard attaches to this small hole.
Mouse: It is generally the same size and shape as the keyboard connector, although there is a mouse icon near this slot to let you know that a mouse is plugged into it.
USB: Plug stylish devices into certificate-sized Universal Serial Bus (USB) slots.
COM/Serial: Computers have at least one of these connectors.
Video/VGA: Your computer monitor can be connected to this slot. The video connector is about the same size as the COM/serial connector, but has 15 holes instead of 9.
SPDIF In and SPDIF Out: These connectors are used for digital audio. A special fiber-optic cable is required: the audio entering the computer into the internal slot; The sound generated by the computer is output from the output slot.
Speakers/Speakers: In this slot, you connect external speakers or headphones to your computer, or where you connect your computer to an audio system.
Line In: This jack is where you connect a traditional audio production device (stereo, phonograph, VCR, etc.) to your computer to capture audio.
Left/Right surround sound: Also for surround sound, this is the jack you connect the left and right rear speakers.
Center/Subwoofer: For a surround sound system, you can plug the center speaker, subwoofer, or both into this jack.
Microphone: A computer microphone is connected to this jack.
Modem: This is where you plug your dial-up modem into your computer into a phone jack in the wall. If there are two slots for the phone or modem on the input / output panel, then the second slot is for extending the phone.
Network: This is where you connect a local area network (LAN) connector or where you connect a broadband modem to your computer.
Printer: Older printers can be connected to this connector.
Mini 1394: This special version of the IEEE 1394 connector is designed specifically for digital video and for connecting digital cameras.
IEEE 1394 (FireWire): This is another type of versatile connector, similar to USB.