Nokia Code Function
*3370# This Nokia code activates Enhanced Full Rate Codec (EFR) - Your Nokia cell phone uses the best sound quality but talk time is reduced my approx. 5%

#3370# Deactivate Enhanced Full Rate Codec (EFR)

*#4720# Activate Half Rate Codec - Your phone uses a lower quality sound but you should gain approx 30% more Talk Time

*#4720# With this Nokia code you can deactivate the Half Rate Codec

*#0000# Displays your phones software version, 1st Line : Software Version, 2nd Line : Software Release Date, 3rd Line : Compression Type