Android secret codes fall into two primary categories: MMI (Man-Machine Interface) codes and USSD (Unstructured Supplementary Service Data ... access to diagnostic menus and technical information ...

Let’s start by explaining what is USSD (Unstructured Supplementary Service Data ... do tests or access hidden menus in our Android phones. Some codes will refuse to work on certain models ...

If your Android device is acting up or you just want to delve deep into the system with some cool secret codes, this list is for you. The Redmond Pie has compiled a handy list of many secret codes ...