Most of the input and output devices are on the outside of the computer case. These devices communicate with components inside the computer case, either by wireless connection or cables attached to the case at a connection called a port. Most of these computer ports are located at the rear of the computer case, although some computer models do have some ports on the front of the case for easier access.
For wireless connections, a wireless device communicates with the computer using a radio wave or infrared port. the most popular of these devices are the keyboard and the mouse, and the most popular output devices are the monitor and the printer.
The keyboard is the main input device of a computer. Standard keyboards today are called enhanced keyboards and hold 104 keys and come in different shapes and sizes, and there are also ergonomic design's making them more comfortable for the hands and wrists.
A mouse is a pointing device and is used to move a pointer on the screen and to make selections. The bottom of the mouse has a rotating ball or an optical sensor which tracks movement and controls the location of the pointer on the screen. the buttons on top of the mouse are used for different purposes for different software. For example windows XP uses the left mouse button to execute commands and the right mouse button to display information about the command.
The monitor is the visual device which displays the main output of the computer. Hardware manufacturers typically rate a monitor according to the size of the screen (in inches) and by the monitor's resolution, which is the function of the number of dots on the screen used for display.
The printer is a very important device, which produces output on paper, this is usually called a hard copy. the most common printers today are the laser and inkjet printers although there are other types of printers available, like the thermal, solid ink and dot matrix printers.