Portable CD player
A portable CD player is a portable audio player used to play compact discs. The first audio player released was the Discman D-50 by Sony. Features. The basic features of a portable CD player are: The play and pause feature allows the user to pause in the middle of the track (song) and resume it at the same place the listener left off at once the play button is hit again. The stop feature stops the track allowing the user to then switch tracks easily. The fast forward and rewind feature will either fast forward or rewind  the track the amount of time you hold the button down. The liquid crystal display provides a visual of how much battery is left, what track (number) is currently playing, and the amount of time elapsed on the track. Some portable CD players can play CD-R/CD-RW discs and some can play other formats such as MP3-encoded audio. While audio typically is output via a headphone connector, higher-end models may feature an additional integrated speaker. The 8 cm CD provides a smaller alternative to the normal 12 cm CD (although with a lower capacity). Miniature players  exist that only play this format. Some portable CD players feature an externally attached playback controller as depicted, to facilitate control while the main unit is placed in a bag or pockets. Issues with recordable CDs. Some, mainly earlier portable CD players do not play recordable CDs (CD-R, CD-RW) properly because of the way these CDs are recorded, and due to the significantly lower reflectivity of CD-RW. A consumer-recorded CD is recorded by making marks in a thin layer of organic dye, which leads to incompatibility with some CD players. For some users of CD-Rs , the solution to this is to burn the CD at a slower speed or use a different brand of recordable CDs. Burning at too slow a speed can also cause issues. Ideally, CD-Rs should be burned at half their rated maximum speed, for example, a CD-R with a maximum rating of 48x should be burned at 24x. Future. Portable CD players are declining in popularity since the rise in popularity of Portable media players that play digital audio files including the iPod and smartphones. Before digital audio players became popular, many switched over to MiniDisc as an alternative  to CDs, due to the compact size of the MiniDisc format.