What is the code that make Nokia phones louder?

Many people say that there is a code for any Nokia mobile phone that makes the volume,speaker louder or the code boost loudness.Well let me tell you one thing there is no such code that makes you cell phone loud for Nokia,Sony Ericsson and Motorola mobile phones its just a rumor that goes around in circles.Yes there are secret codes for Nokia,Sony Ericsson and Motorola mobile phones but no loudness codes at all.There are only codes for older slider style Samsungs like the D500 that had that little plug in sound mate speaker.