How do you know that the other party called after the iphone is black?

Little red dot will be displayed next to the screen.

After hacking the other party on the Apple phone, the other party will call you, and a little red dot will be displayed next to the phone screen, indicating that the number has been hacked. The blacked-out number will not have a prompt tone, only little red dot's prompt. This is the default behavior of Apple's mobile phone, which aims to remind users that there are hacked numbers trying to contact.