Ringtone

A ringtone is the sound made by a telephone to indicate an incoming telephone call. Originally referring to the sound of electromechanical striking of bells or gongs, the term refers to any sound by any device alerting of an incoming call.

On plain old telephone services (POTS), starting in the late 19th century, the signal is created by superimposing ringing voltage on the direct current line voltage. Electronic telephones could produce a warbling, chirping, or other sounds. Variations of the cadence or tone of the ring signal, called distinctive ringing, can be used to indicate characteristics of incoming calls.

Modern telephones, especially smartphones, are manufactured with a preloaded selection of ringtones. Customers can buy or generate custom ringtones for installation on the device. Digital ringtones were a large market in the 2000s, at its peak generating up to $4 billion in worldwide sales in 2004, but the market declined steeply by the end of the decade.