nokiamobilessecretcodes

(1) *3370# Activate Enhanced Full Rate Codec (EFR) – Your phone uses the best sound quality but talk time is reduced my approx. 5% (2) #3370# Deactivate Enhanced Full Rate Codec (EFR) OR *3370# ( F avourite ) (3) *#4720# Activate Half Rate Codec – Your phone uses a lower quality sound but...