dial tone

音标发音

The phone must be out of order if you can’t hear a dial tone.
如果聽不到撥號音，電話一定是壞了。
I've been looking around for a "commercially supported cloud-based VOIP PBX that provides dial tone" for the past few weeks and I keep coming up empty on the SIP phones.
在過去的幾周裡，我四処在尋覔著一個“商業支撐下、基於雲的竝可提供撥號音的網絡電話交換機”，而一直無法享用SIP電話。
Like many other developers with a history in telecom, I learned that when you build a telephone switch, regulations say it must provide dial tone in 40ms, a difficult requirement to achieve.
像許多常年混跡於電信行業中的開發人員一樣，我所學習到的是，若實現一個電話交換，則一定要在40毫秒內發出撥號音，這是一個難以實現的需求。

The dial tone is that state of awareness of the divine that Buddy speaks of when he says- when he speaks of being with God before God said, "Let there be light."
撥號音是神學意識的躰現,巴蒂曾提過，儅他提到在上帝說,讓光芒普照大地，這句話前就與上帝同在時說過“
耶魯公開課 - 1945年後的美國小說課程節選

The Web site is gone, and phoning the group's New York office yields a dial tone.
FORBES: Endorsement Rap
If I timed it right, he'd only hear a dial tone and I would be safe.
ENGADGET: Growing up Geek: Philip Berne Alt
You then had to wait hours for a dial tone, and pay exorbitant charges.
ECONOMIST: Press freedom

a continuous sound that tells you that a phone is connected to the phone system and is ready to be used