Cell phone ringtone

I should say, a ring tone is the sound made by a telephone to indicate an incoming call. The term, however, is most often used to refer to the customisable sounds available on mobile phones. This 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.

A phone only rings when a special "ringing signal" is sent to it. For regular telephones, the ringing signal is a 90-volt 20-hertz AC wave generated by the switch to which the telephone is connected. For mobile phones, the ringing signal is a specific radio-frequency signal.

Newer mobile phones allow the users to associate different ringtones for different phonebook entries. Many also allow users to create their own music tones, either with a "melody composer" or a sample/loop arranger (such as the MusicDJ in many Sony Ericsson phones). Often these are native formats only available to one particular phone model or brand. However, other formats, such as MIDI or MP3, are often supported; they must be downloaded to the phone before they can be used as a normal ringtone. Commercial ringtones take advantage of this functionality, which has led to the success of the mobile music industry.