There is no sound in the text message sent by phone.

When he is turned on, you dial his number and he will receive a text message. ....

The phone is busy, please hold on.

In this way, he will receive a prompt, beep/... when answering the phone, he will hear it again, that is, someone is calling again ... you can hang up this phone and answer it again, or you can keep this phone and answer it again. ...

The call is in progress and cannot be connected. ..

There is no hint.