I called a friend yesterday and said welcome to China Mobile. Now that the peer-to-peer SMS service has been launched, it will help you inform you that this is the other party's power off.

There are several situations that will be notified.

1, the other party is busy. You can hear this by listening to the playback. If there is a busy signal, remind the other party that it is on the phone, and then remind you that the other party has opened a business.

2. When the other party shuts down, you will first hear the other party shut down, and then remind you that the other party has started business.

If the other party doesn't answer, you can't hear the broadcast at this time. You can only hear the ringing of the other party, and remind you that the other party has started business after a period of time.

3, the other party is no longer in the service area, that is, unplug the battery without signal or power off. At this time, you will first hear that you can't connect, and then the other party will remind you when it opens the business.

I estimate that your situation is "the other party doesn't answer"