A ringback tone is an audible indication that is heard on the telephone line by the caller while the phone they called is still in use. It is normally a repeated tone, designed to assure the calling party that the called party’s line is ringing.
Ringback tone（接通迴音）指電話處於正常使用狀態時，打電話的人從聽筒中聽到的聲音提示。這種聲音一般都是一個重複的音調，目的只是提示打電話的人，對方的`電話正在接通中。
Ringback music, also called personalized ringback tone, is a piece of music heard by the caller instead of the traditional telephone ring signal when a telephone call is placed.
Ringback music（“個性化接通迴音”）則是打電話時，傳統的電話提示音被音樂所取代，於是成爲了我們所說的“彩鈴”。
