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.
受話器を取ると発信音が聞こえた。
When I picked up the receiver, I heard a dial tone.
電話をかけると、発
When I made the call, after the ringback tone the other party answered.