• A phone only rings when a distinctive "ringing signal" is sent to it

• For regular telephones, the ringing signal is a 90-volt, 20-hertz, AC billow generated by the switch to which the telephone is connected
• For mobile phones, Ring Tones the ringing signal is a specific radio-frequency signal.

A telephone ring is the sound generated when an incoming telephone call is received. The title originated from the fact that telephones notified the user to an incoming call by repeatedly striking a bell or bells, producing a ringing sound.