A ring tone is the sound made by a telephone to braodcast that there is an incoming call. The term is most often used to refer to the customisable sounds available on mobile phones. Ringtones were originally provided so that people would be able to determine when their phone was ringing when in the company of other mobile phone owners. A phone only rings when a special "ring signal" is sent to it. For regular phones, the ring signal is a 90-volt 20-hertz AC wave generated from the switch that the telephone is connected to. For mobile phones, the ring signal is a specific radio-frequency signal.
A new version of ring tones, often called either music ring tones, voice tones, realtones, singtones or true tones, now use actual pieces from songs, along with all the lyrics and the entire song backing music, including backing singers. They are usually contained in AAC, MP3, WMA, WAV, QCP, or AMR format that can be used as a ring tone on many phones. Ringtones are just another way of customizing your mobile phone to your personal taste.