These codes (all but one) are manufacturer dependent and in certain cases network dependent, so your mileage with them may vary.
Starting with the universal ones
Typing this will reveal you IMEI (international mobile equipment identity) number across brands and handsets (it is a regulation). Every phone has a unique number and technically if your phone is lost it is possible to trace it via this number even if the thief changes the network. In regions such as Europe this actually happens in practice, but in India things are a little slack. While buying a phone always match this number (which comes on screen) with the number printed on the backside (battery compartment) of your phone and the box in which the phone has come. All three should be same, including a genuine phone.
This is not really a code but a emergency number. You will be able to dial this number even if the keypad is locked and will be able to dial independent of the presence of your network, till any cellphone network is available within range. This will also work if you don’t have credit. In some states in India 108 is your emergency number, through it won’t work without removing the keypad lock.
Codes for Nokia phones
Reveals the production serial number, confirm to work on Series 40 phones, doesn’t work on all series 60.
Proceed with caution, this shall reset your phone to factory settings. Useful if you are debugging and are confused if the problem is software settings related or hardware.
Very useful, tells you your current firmware version. In phones which support OTA (over the air) updating, you can simply update your phone firmware from the option menu that this will bring via GPRS/3G/Wi-Fi without connecting to the PC Suite.
Reveals your Bluetooth device address, some manual configuration needed for settings up your custom Bluetooth device or troubleshooting may require this information.
Allows you to check the number where “All Calls” are diverted to.
· *#30# and press dial
Lets you see the private number. Network dependent.
Allows you to check the “Call Waiting” status of your phone.
Allows you to check the number that “On No Reply” calls are diverted to
Allows you to check the number that “Divert If Unreachable (no service)”calls are diverted to
Allows you to check the number that “On Busy Calls” are diverted to
Turn on “All Calls” diverting to the phone number entered
Turn on “No Reply” diverting to the phone number entered
Turn on “On Busy” diverting to the phone number entered
Gives you the following information, but works only on very low-end and old nokia phones.
-> * <- <- * <- *
(-> means press joystick towards right and <- means left) This brings up the secret menu in a Sony Ericsson phone which contains the following information and functions:
· Service Info
· Model Info
· Software Info
· Sim lock status
· Service Settings
· USB charging ON/OFF
· Service Tests
· Main Display
· Memory Stick
· FM Radio
· Real Time Clock
· Total Call time
· <- * * <-
SIM lock Status. This is another good check before you buy anyphone, especially second handones. If phone is SIM locked, you may not be able to switch to other GSM operators.
This is quick way to dial the last dialed number.
Changes back to default language and theme, very useful if the language is changed to something else, as at that time menu navigation is extremely difficult.
There are many more esoteric and nearly useless codes available which works on much selected section of devices, for the sake of generally we have omitted them over here.
Exercise caution while playing with all the above secrets codes and have fun.