0 a continuous sound that tells you that a phone is connected to the phone system and is ready to be used -- （電話）撥號音
For the first time, subscribers heard a dial tone upon lifting the receiver, instead of the familiar question: number please.
The exchange provides dial tone at that time to indicate to the user that the exchange is ready to receive dialed digits.
When a user picks up the phone, the concentrator produces the dial tone.
An analogue telephone line may send tones such as a busy signal, reorder tone or dial tone to indicate a call has ended.
The central office sends dial tone and the rest of the call proceeds normally.
After the user listens to the dial tone, user enters the destination number to which they want to dial.
More consistently, the forwarded line indicates its condition by stutter dial tone.
Users also have access to all of their dial tone, voicemails, e-mails and faxes from any connected endpoint.
