A free program for Android, by mdn.
USSDDualWidget is a free tool for Android that allows you to get information from your mobile phone. The application uses the phone's built-in microphone to listen for a specific sound. When the sound is heard, the application will display the information that is heard.
There are several different sounds that can be heard. The information that is displayed includes the name of the caller, the time of the call, the number of the caller, the message that was sent, the type of message that was sent, and more.
If the user is on the phone, the application will also display the current battery level and the date and time.