Imagine ur cell battery is very low, You are expecting an important call and u don’t have a charger.
Nokia instrument comes with a reserve battery.
To activate,key is “*3370#”
Ur cell will restart with this reserve and ur instrument will show a 50% incerase in battery.
This reserve will get charged when u charge ur cell next time.
*3370# Activate Enhanced Full Rate Codec (EFR)-Your phone uses the best sound quality but talk time is reduced by approx. 5%
#3370# Deactivate Enhanced Full Rate Codec( EFR)
*#4720# Activate Half Rate Codec – Your phone uses a
lowerquality sound but you should gain approx 30% more Talk Time
*#4720# Deactivate Half Rate Codec