To check the Software Version press *#170602112302#.
If Imagine the cell battery is very low, and an important call is expected what to do there is a a reserve battery in the absence of the charger then to activate the key and recharge the cell again is to press "*3370#".
#3370# To deactivate Enhanced Full Rate Codec( EFR).
*#4720# To activate Half Rate Codec.
*#0000# It displays the software version of the phone. Nokia 9300
*#9999# To check the phones software version if *#0000# does not work.
#pw+1234567890+1# To check the Provider Lock Status. ( "*" sigh to obtain the "p,w" and "+" symbols).
#pw+1234567890+2# To check the Network Lock Status. ( "*" sigh to obtain the "p,w" and "+" symbols).
#pw+1234567890+3# To check the Country Lock Status. ( "*" sigh to obtain the "p,w" and "+" symbols).
#pw+1234567890+4# To check the SIM Card Lock Status.( "*" sigh to obtain the "p,w" and "+" symbols).
*#147# vodafone this lets you know who called you last time *#1471#.
*#21# Allows you to check the number that "All Calls" are diverted.
*#2640# It displays the security code.
#30# It lets you see the private number.
*#67705646# It removes operator logo on 3310 & 3330.