A ring tone is the sound made by a telephone to indicate an incoming call. The term is most often used to refer to the customisable sounds available on mobile phones. 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.

A phone only rings when a special "ring signal" is sent to it. For regular telephones, 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.

An alternative to a ring tone is a vibrating alert. It is especially useful:

* in noisy environments
* in places where ring tone noise would be disturbing
* for the hearing impaired

Polyphonic
Polyphonic means that multiple tones can be played at the same time using instrument sounds such as guitar, drums, electronic piano, etc. 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. Mobile phone handsets manufacturers have taken full advantage of new technologies to improve speakers in order to produce a better sound quality.

The quality of a polyphonic ringtone is much higher than a monophonic ringtone. If your mobile handset does not support mp3 ringtones, then polyphonic ringtones are the best you can opt for. But in case your handset supports mp3, then that is the option you should go for. By the way, polyphonic ringtones are also available free of cost but there are some select ringtones that are also chargeable.

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. Many people enjoy their personalisation of the phones, but some find certain ring tones annoying in public and in certain public situations. One of the classic ring tones was parodied by The Daily Show's Stephen Colbert as "You're annoying/Stupid douchebag/Turn your phone off now"

Many companies have set up businesses selling ring tones, advertising them on television and web sites. One criticism of the industry is the subscription some companies lock customers into, requiring them to actively cancel their account or be charged for unwanted messages and ring tones sent to them on a weekly basis.

The sale of ring tones has also been a massive boost to the record industry, earning them extra revenues through royalties.

The newer phones equipped with Bluetooth or PC-link up however, allow users to transfer ringtones created on a PC, to their phone, for free. The user could even record themselves or their own tones and place them on the phone.