also: ダイヤルトン
dial tone
The continuous tone heard on a telephone line when it is ready to receive a call.
受話器を取るとダイヤルトーンが聞こえた。
When I picked up the receiver, I heard the dial tone.
Clipped form; occasionally used in casual contexts.
Clipped form with interpunct; very rare.
Borrowed from English 'dial tone'.