Is this true ?
You can press *3370# to access reserve mobile phone battery power.
Apparently the code *3370# activates the Nokia Enhanced Full Rate Codec (EFR), this means that the Nokia cell phone has better sound quality, but with a shorter battery life.
To disable this (EFR) feature, the code is *#4720# which reduces voice quality but enhances battery life.
- Nokia.com: http://discussions.europe.nokia.com
- Nokia.com: http://discussions.europe.nokia.com/…/Useful-codes
223.1 - 676,936