found: Wikipedia, Dec. 7, 2009("A ringtone or ring tone is the sound made by a telephone to indicate an incoming call or text message. The term is a misnomer, as it is often used to refer to any ring sound, almost all of which are not tones. The term is most often used to refer to the customizable sounds used on mobile phones.")
found: Work cat.: The little book of pics & tones, 2001:p. 6 (personalizing your image by adding a ringtone to your mobile phone) p. 4 of cover (sounds ranging from Madonna to a wolf whistle or the theme tune of your favourite TV show)
found: WordiQ.com, Feb. 8, 2005(Ring tone. The facility was originally provided so that people would be able to determine when their phone was ringing when in the company of other mobile phone owners. Ring tones, along with operator logos, have proven a popular method of personalising phones a major industry has popped up to tailor to the needs of people to customise their phones, and newer phones include features to allow users to create their own tones. Monophonic Ringtones: Early phones had the ability to have ring tones programmed into them using an internal ringtone composer. Later, various formats were developed to enable ring tones to be sent via text using RTTL encoding. Polyphonic Ringtones: Many phones are now able to play more complex polytones; up to 40 individual notes with different instruments are played simultaneously to give a more realistic musical sound)