What does Unicom mean by reminding you that the subscriber you dialed is busy?

1, the other party is on the phone. When the other party is on the phone, the system will automatically prompt you that the number you dialed is busy;

2. The other party's mobile phone is turned off. If the other party's mobile phone is turned off, you will also prompt the other party to be busy when you call;

3. The other party's signal is not in service area. When the other party's number is not in the service area because of the signal, it will prompt that the phone is busy when making a call;

4. The other party has set up interference interception, such as blacklisting you or setting your mobile phone to flight mode. This will happen when you call the other party.