The ringing signal in North America is normally specified at ca. (SLC is a trademark of Alcatel-Lucent, but is often used generically.) Telephones with electromagnetic ringers are still in widespread use. This is done at the Central Office, or a neighborhood multiplexer called an "SLC" for Subscriber Line Carrier. On a POTS interface, this signal is created by superimposing ringing voltage atop the −48 VDC already on the line.
For mobile phones, the network sends a message to the recipient's device, which may activate a sound, or a visual or vibrating indication. The ringing current originally operated an electric bell. Landline telephones typically receive an electric alternating current signal, called power ringing or ringing signal, generated by the telephone exchange to which the telephone is connected. Digital ringtones were an enormous 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.Ī telephone rings when the telephone network indicates an incoming call, so that the recipient is alerted of the call attempt. Customers can buy or generate custom ringtones for installation on the device. Modern telephones, especially smartphones, are manufactured with a preloaded selection of ringtones. Variations on the ring signal can be used to indicate characteristics of incoming calls. Electric phones could electronically produce a warbling, chirping, or other sounds. On plain old telephone services (POTS), starting in the late 19th century, the required signal is created by superimposing ringing voltage atop the existing voltage. Originally referring to and made by the electromechanical striking of bells, the term now refers to any sound on any device alerting of a new incoming call-up to and including recordings of original telephone bells.
Ringing noise from an electromechanical telephone Example of a short digital tune which could be used as a ringtone on a mobile phone Electromechanical ringer in a 20th century landline telephoneĪ ringtone, ring tone or ring is the sound made by a telephone to indicate an incoming call. For other uses, see Ringtone (disambiguation).
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