*#06# for checking the IMEI (International Mobile Equipment Identity).
*#7780# reset to factory settings.
*#67705646# This will clear the LCD display (operator logo).
*#0000# To view software version.
*#2820# Bluetooth device address.
*#746025625# Sim clock allowed status.
*#62209526# – Display the MAC address of the WLAN adapter. This is available only in the newer devices that support WLAN
#pw+1234567890+1# Shows if sim have restrictions.
*#92702689#
*#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.
*#4720# - Half Rate Codec activation.
*#4720* - Half Rate Codec deactivation. The phone will automatically restart
*#7328748263373738# resets security code.