In order to enter these codes, the phone must be in the idle screen, not in any of the menu screens. The idle screen is where you see the operator name, date, time, battery level, signal strength.
*#06# - Displays the IMEI (GSM standard).
*#2820# - Displays the Bluetooth device address of your phone.
*#62209526# - Displays the MAC address of the WLAN (wireless lan) adapter. This is available only in the newer devices that support WLAN.
*#7370# - Resets your phone to the default factory settings. Usually you will need this code when you want to reset your phone back to the same condition when you got it for the first time. When the phone ask for security code, the default one is 12345 unless you have specified one yourself.
Warning: Before you do reset the phone, make sure that you don’t have important data and that you know the security code for your phone. Your data on the phone memory will be lost once you reset it.
*#7780# - This will soft reset your phone. It is different from *#7370# because all data, like contacts, calendar and notes, are not removed. It will only reset the phone settings, such as profiles, themes and shortcuts. The default lock code is 12345.
*#0000# - To view software version.
*#67705646# - This will clear the LCD display(operator logo).
*#92702689# - Takes you to a secret menu where you may find some of the information below:
1. Displays Serial Number.
2. Displays the Month and Year of Manufacture
3. Displays (if there) the date where the phone was purchased (MMYY)
4. Displays the date of the last repair - if found (0000)
5. Shows life timer of phone (time passes since last start)
*#3370# - Enhanced Full Rate Codec (EFR) activation. Increase signal strength, better signal reception. It also help if u want to use GPRS and the service is not responding or too slow. Phone battery will drain faster though.
*#3370* - (EFR) deactivation. Phone will automatically restart. Increase battery life by 30% because phone receives less signal from network.
If you forgot wallet code for Nokia S60 phone, use this code to reset: *#7370925538#
Note, your data in the wallet will be erased. Phone will ask you the lock code. Default lock code is: 12345 .