Ringtone
A ringtone or ring tone is the sound made by a telephone to indicate an incoming call or text message. Not literally a tone nor an actual (bell-like) ring anymore, the term is most often used today to refer to customizable sounds used on mobile phones. Background. A telephone rings when the telephone network indicates an incoming call, so that the recipient is alerted of the call attempt. 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. The ringing current originally  operated an electric bell. For mobile phones, the network sends a message to the recipient's device, which may activate a sound, or a visual or vibrating indication. On a POTS interface, this signal is created by superimposing ringing voltage atop the −48 VDC already on the line. This is done at the Central Office, or a neighborhood multiplexer called a "SLC" for Subscriber Line Carrier. (SLC is a trademark of Alcatel-Lucent, but is often used generically.) Telephones with electromagnetic ringers are still in widespread use. The ringing signal in North America is normally specified at ca. 90 volts  AC with a frequency of 20 hertz. In Europe it is around 60–90 VAC with a frequency of 25 Hz. Some non-Bell Company system party lines in the US used multiple frequencies for selective ringing. Ringing voltage is produced by various sources. Large central offices used motor-driven generator sets for both ringing and other signals such as dial tone and busy signals. In smaller offices, special sub-cycle magnetic oscillators were used. Typically, solid-state oscillators have replaced them. Originally this voltage was used to trigger an electromagnet to ring a bell installed inside the telephone, or in  a nearby mounted ringer box. Fixed phones of the late 20th century and later detect this ringing current voltage and trigger a warbling tone electronically. Mobile phones have been fully digital since the early 1990s second-generation ("2G") devices, hence are signaled to ring as part of the protocol they use to communicate with the cell base stations. While the sound produced is still called a "ring", more-recently manufactured telephones electronically produce a warbling, chirping, or other sound. Variation of the ring signal can be used to indicate characteristics of incoming calls. For example, ringing bursts with a  shorter interval between them might be used to signal a call from a given number. In POTS switching systems, ringing is said to be "tripped" when the impedance of the line reduces to about 600 ohms when the telephone handset is lifted off the switch-hook. This signals that the telephone call has been answered, and the telephone exchange immediately removes the ringing signal from the line and connects the call. This is the source of the name of the problem called "ring-trip" or "pre-trip", which occurs when the ringing signal on the line encounters excessively low resistance  between the conductors, which trips the ring before the subscriber's actual telephone has a chance to ring (for more than a very short time); this is common with wet connections and improperly installed lines. The ringing pattern is known as ring cadence. This only applies to POTS fixed phones, where the high voltage ring signal is switched on and off to create the ringing pattern. In North America, the standard ring cadence is "2-4", or two seconds of ringing followed by four seconds of silence (33% Duty Cycle). In Australia and the UK, the standard ring cadence is  400 ms on, 200 ms off, 400 ms on, 2000 ms off. These patterns may vary from region to region, and other patterns are used in different countries around the world. Some central offices offer distinctive ring to identify which of multiple numbers on the same line is being called, a pattern once widely used on party line (telephony). In many systems, including North America Bellcore standards, Caller ID signals are sent during the silent interval between the first and second bursts of the ringing signals. The caller is informed about the progress of the call by the audible ringing  signal, often called ringback tone. Power ringing and audible ringing are not synchronized. History. AT&T offered seven different gong combinations for the "C" type ringer found in the model 500 and 2500 landline telephone sets. These gongs provided "distinctive tones" for hearing-impaired customers and also made it possible to distinguish the specific telephone that was ringing when several telephones were placed in close proximity. A "Bell Chime" was also offered, which could be set to sound like a doorbell or to ring like a standard telephone. While rings, ringers, ring signals, or what might be viewed as the call  signals which are the predecessors of ringtones, date back to the beginnings of telephony, modern ringtones appeared in the 1960s and have expanded into tunes and many customizable tones or melodies. Arguably the first ringtone (in the modern sense) appeared in the movie "Our Man Flint" in 1966, where the head of the secret government agency had a red phone that connected directly to the President and rang with a distinctive musical ringtone. Following a 1975 FCC ruling which permitted third-party devices to be connected to phone lines, manufacturers produced accessory telephone ringers which rang with electronic tones or  melodies rather than mechanical bells. People also made their own ringers which used the chip from a musical greeting card to play a melody on the arrival of a call. One such ringer, described in a 1989 book, even features a toy dog which barks and wags its tail when a call arrives. Eventually, electronic telephone ringers became the norm. Some of these ringers produced a single tone, but others produced a sequence of two or three tones or a musical melody. Some novelty phones have a ringer to match, such as a duck that quacks or a car that  honks its horn. In September 1996, IDO, the current au, sold Digital Minimo D319 by Denso. It was the first mobile phone where a user could input an original melody, rather than the preset songs. These phones proved to be popular in Japan: a book published in 1998 providing details about how to customize phones to play snippets of popular songs sold more than 3.5 million copies. The first downloadable mobile ring tone service was created and delivered in Finland in 1998 when Radiolinja (a Finnish mobile operator now known as Elisa) started their service called Harmonium, invented by Vesa -Matti Pananen. Harmonium contained both tools for individuals to create monophonic ring tones and a mechanism to deliver them over-the-air (OTA) via SMS to a mobile handset. In November 1998, Digitalphone Groupe (SoftBank Mobile) started a similar service in Japan. Generation software. A ring tone maker is an application that converts a user chosen song or other audio file for use as a ringtone of a mobile phone. The ringtone file is installed in the mobile phone either by direct cable connection, Bluetooth, text messaging, or e-mail. On many websites, users may create ring tones from digital  music or audio. The earliest ringtone maker was Harmonium, developed by Vesa-Matti Paananen, a Finnish computer programmer, and released in 1997 for use with Nokia smart messaging. Andy Clarke, while working for UK Phone Provider Orange, helped created the B5 Ringtone License with the UK's Mechanical-Copyright Protection Society in 1998. In 1999, Clarke registered ringtone.net and setup what is believed to be the world's first "legal" ringtone business. Scott Memphis, leader singer of Sunday Morning Sanctuary, wrote a 2010 hit entitled, "Ringtones & Lullabies" inspired by with the B5 Ringtone Licensing of 1998. Some providers have features  for users to create music tones, either with a "melody composer" or a sample/loop arranger, such as the MusicDJ in many Sony Ericsson phones. These often use encoding formats only available to one particular phone model or brand. 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 ring tone. When someone buys a ringtone, an aggregator (a company that sells ringtones) either creates the tune or mixes a pre-existing tune. The ringtone is sent in a special file format to the phone  via SMS. If the company uses a pre-existing song, they must pay royalties to a licensing agency. A significant portion goes to the cell phone provider. In 2005, "SmashTheTones", now "Mobile17", became the first third-party solution for ring tone creation online without requiring downloadable software or a digital audio editor. Later, users of Apple's iPhone could create a ringtone from a song purchased with the iTunes library. Commercial sales and popularity. The fact that consumers were willing to pay up to $3 for ringtones, made mobile music a profitable part of the music industry. The Manhattan -based marketing and consulting firm Consect estimated ringtones generated $4 billion in worldwide sales in 2004. According to "Fortune" magazine, ring tones generated more than $2 billion in worldwide sales during 2005. The rise of sound files also contributed to the popularization of ringtones. In 2003 for example, the Japanese ringtone market, which alone was worth US$900 million, experienced US$66.4 million worth of sound file ringtone sales. In 2003, the global ringtone industry was worth somewhere between US$2.5 and US$3.5 billion. In 2009, the research firm SNL Kagan estimated that sales of ringtones in  the United States peaked at $714 million in 2007. SNL Kagan estimated U.S. sales in 2008 declined to $541 million, as consumers utilized third-party software and tutorials to create ringtones themselves. Preloaded ringtones have also developed a cult following over the years. A Twitter account named Ringtone Bangers + More launched in 2020, posts preloaded ringtones from mobile phones on a daily basis, as well as other music related to technology such as demoes from keyboards and software installation background music. The account has also published interviews with composers who worked on ringtones. Encoding formats. Most modern  phones support ringtones in MP3 format, and other common audio formats such as AAC, Ogg Vorbis, FLAC, and MIDI are often supported as well. Less common formats include: