ring tone

A phone "rings" when the network indicates an incoming call and your phone that alerts the user. For phones, the call sign of an electric current generated by the switch or exchange in which the phone is connected. For mobile phones, the network sends the phone a message indicating an incoming call.

A telephone "ring" is the sound generated when an incoming call. The term derives from the fact that initially phone is ringing mechanism consisting of bubbles, and an electromagnetically actuated valve, resulting in a ringing tone. The electromagnets mentioned electric signal strength soon go ahead and leave the door, striking the bells. This is the electromagnetic system clock, is still widely used. The ringing of the phone to a customer is 90 volts AC with a frequency of 20 Hz in North America. In Europe, it is 60-90 volts AC at a frequency of 25 Hz Some lines of non-Bell System in the U.S. party use multiple frequencies (20/30/40Hz, 22/33/44 Hz, etc) for "selective" call possible.

In Australia, the average ring 100 V AC at 25 Hz [1]

Although the sound produced is still a "ring" more recently manufactured telephones electronically produce a warbling, whistling or other sounds. The variation of the ring signal can be used to define the characteristics of incoming calls (for example, rings with a shorter interval may be used to make a call to a given number of signal response).

A ringing signal is an electric telephony signal that causes a telephone to alert the user to an incoming call. In the POTS interface This signal is created by superposition of ringing voltage [90 volts AC at 20 Hz in the USA], besides those already on the line-48VDC. This is done by the Central Bank a multiplexer or neighborhood is called a "SLC" Subscriber Line Carrier. (SLC is a trademark of Alcatel-Lucent, but it is a general term often used.