![]() ![]() Fixed phones of the late 20th century and later detect this ringing current voltage and trigger a warbling tone electronically. ![]() Originally this voltage was used to trigger an electromagnet to ring a bell installed inside the telephone, or in a nearby mounted ringer box. Typically, solid-state oscillators have replaced them. In smaller offices, special sub-cycle magnetic oscillators were used. Large central offices used motor-driven generator sets for both ringing and other signals such as dial tone and busy signals. Ringing voltage is produced by various sources. Some non- Bell Company system party lines in the US used multiple frequencies for selective ringing. In Europe it is around 60–90 VAC with a frequency of 25 Hz. 90 volts AC with a frequency of 20 hertz. 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 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.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 of the cadence or tone of the ring signal, called distinctive ringing, can be used to indicate characteristics of incoming calls. Electronic telephones could produce a warbling, chirping, or other sounds. 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. 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. 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 is the sound made by a telephone to indicate an incoming telephone call. For other uses, see Ringtone (disambiguation). ![]()
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