All computers and computer programs process information in three different and sequential stages: input, processing of input and output of the results. For the computer user to receive the output results from the computer, the computer needs to have components that can visually display those results. There are a variety of devices that act as computer output devices. These devices can be connected to the computer through a wireless or wired connection.
A modern computer's main way of outputting data is through its monitor. When a user inputs a command via the keyboard, an input device, the computer processes that command and outputs the results via the monitor. Monitors may be CRTs, flat-panel LCD screens or touchscreens.
Speakers output data in audio format, including music, movie audio and text-to-speech output. Speakers are not usually necessary, but may enhance the computing experience. Headphones are also a type of speaker.
Printers produce a physical form of output. Word processed documents or edited photos are made into a hard copy by printing. As computer technology has evolved, so has printer technology. There are four main types of printers: laser, inkjet, dot-matrix and thermal.