Found today a post

  1. Go to phone app
  2. Dial *#*#4636#*#*
  3. See secret test menu:)

*#*#4636#*#*

I’ve looked deep into platform code. Here’s are the code from Phone.git

    static boolean handleSecretCode(Context context, String input) {
        // Secret codes are in the form *#*#<code>#*#*
        int len = input.length();
        if (len > 8 && input.startsWith("*#*#") && input.endsWith("#*#*")) {
            Intent intent = new Intent(Intents.SECRET_CODE_ACTION,
                    Uri.parse("android_secret_code://" + input.substring(4, len - 4)));
            context.sendBroadcast(intent);
            return true;
        }

        return false;
    }

So, let’s search for Intent filters:

Settings.git

        <receiver android:name="TestingSettingsBroadcastReceiver">
            <intent-filter>
                 <action android:name="android.provider.Telephony.SECRET_CODE" />
                 <data android:scheme="android_secret_code" android:host="4636" />
            </intent-filter>
       </receiver>

CalendarProvider.git (this one works only on >2.0)

        <receiver android:name="TestingSettingsBroadcastReceiver">
            <intent-filter>
                 <action android:name="android.provider.Telephony.SECRET_CODE" />
                 <data android:scheme="android_secret_code" android:host="225" />
            </intent-filter>
       </receiver>

VoiceDialer.git

      <!--  Voice Dialer Logging Enabled, *#*#VDL1#*#* -->
      <intent-filter>
        <action android:name="android.provider.Telephony.SECRET_CODE" />
        <data android:scheme="android_secret_code" android:host="8351" />
      </intent-filter>

      <!--  Voice Dialer Logging Disabled, *#*#VDL0#*#* -->
      <intent-filter>
        <action android:name="android.provider.Telephony.SECRET_CODE" />
        <data android:scheme="android_secret_code" android:host="8350" />
      </intent-filter>

You can add your own codes!:)

//DL