Ringing tone

The tone is typically a repeated cadence similar to a traditional power ringing signal (ringtone), but is usually not played synchronously.

With modern cell phone and smartphone technology ringing tone can be customized and even used for advertising.

It may also be generated in the distant switch, transmitted in-band, so that in analog networks the caller could monitor the quality of the voice path of the connection before the call is established.

However, in formal telecommunication specifications that originate in the Bell System in North America, ringback has a different definition.

[2] It is also needed for coin-telephone lines to ring the telephone when the customer has hung up prematurely, for example to collect required overtime charges.

Many European, Asian, and Latin American countries use tones that follow or take inspiration from the ETSI recommendations.

The ETSI tone is also part of GSM mobile standards and can be generated by handsets to indicate ringing, and is frequently used on VoIP and PBX equipment, particularly of European origin.

[citation needed] Variations of this tone have been used since the introduction of automatic switching in Europe in the early 20th century.

The United Kingdom, Ireland, Australia, New Zealand, Hong Kong, and other countries with historical links to British General Post Office (GPO) standards, use a double ring.

Historically, pre-digital systems used the same ringing cadence, but used several different tones depending on the type of equipment in use.

The first functional ringing tone replacement system was invented by Karl Seelig (U.S. patents 7,006,608 and 7,227,929).

[5] Also known as caller tunes in some countries, such as India,[6][better source needed] ringback music is a service offered by mobile network operators that allows subscribers to select a melody, music, tone, song or even personalized recorded sounds as a Ring-Back tone for all of their callers.

4Play Digital workshop accumulated several hundred thousand users of their service in the first few months of commercial deployment, and received an innovation award in February 2009 at the Mobile World Congress in Barcelona.

In May 2011, Adfortel started the first ad-sponsored calling service in Austria with Orange,[9] with users hearing a targeted advertisement instead of the regular waiting ring tone.

A Juniper Research report released in January 2011 predicts that ringback tone advertising will reach $780 million annually by 2015.