Hidden Secret Codes NOKIA

It activates Enhanced Full Rate Codec (EFR).
*3370# >>

Deactivate Enhanced Full Rate Codec (EFR).
#3370# >>

check nokia phone software version if *#0000# does not work.
*#9999# >>

Displays the current phone security code
*#2640# >> .

Lets you see the private number.
*#30# >>

For checking the International Mobile Equipment Identity in short imei no.
press and hold # >> switch between lines 1 and 2.
*#06# >>

Restore factory settings
*#7780# >>