A Compact Disc player (often written as compact disc player), or CD player, is an electronic device which plays audio Compact Discs. CD players are often installed into home stereo systems, car audio systems, and personal computers. They are also manufactured as portable devices. Modern units support other formats in addition to CDs; such as DVDs, CD-ROMs with audio files and video CDs. DJs often use players with adjustable playback sampling rate to alter the pitch of the music programme. Many modern CD players also include the capability to play MP3 CD's. CD playback functionality is also available on all modern CD-ROM/DVD-ROM drive equipped computers as well as on DVD players and CD-ROM/DVD-ROM based game consoles.
Most home CD players are contained in a plastic casing, which also houses the electrical system and the user interface. CD players designed for car audio systems or computers generally have a front casing and exposed sides and back, as these parts will be covered by the car or computer.
The housing of a portable CD player also contains ports used to connect the player to a powered or unpowered speaker, headphones and/or a power system (see electrical wiring in the United States or in the UK). A portable CD player generally contains an internal power source in the form of batteries.
The housing of a stand-alone CD player contains speakers and perhaps a radio and/or tape deck. CD players used in component audio systems contain a power source, the user interface, and numerous ports to connect the player to the various parts of an audio system.