The sudden unknown sound on the mobile phone may be because the software that trusts unknown sources is selected in the mobile phone settings, so it will be automatically installed after downloading. The installed APP has a prank bug, so it will make an unknown sound. It is recommended to uninstall anti-virus software and scan the mobile phone.

Mobile phones, called mobile phones or wireless phones, are usually called mobile phones. At first, they were just a communication tool. In the early days, it was also commonly known as mobile phone. They are portable telephone terminals that can be widely used. They were originally developed from 1940 battlefield mobile phones manufactured by Bell Laboratories.