発はっ信しん音おん

noun

dial tone; ringback tone; beep

Refers to the tone heard when initiating a call, such as a dial tone or the ringing signal before the other party answers. Also used for electronic beeps.

• 受じゅ話わ器きを取とると発はっ信しん音おんが聞きこえた。

  When I picked up the receiver, I heard a dial tone.

• 電でん話わをかけると、発はっ信しん音おんの後あとに相あい手てが出でた。

  When I made the call, after the ringback tone the other party answered.