Understand your Cell Phone & GSM Technology

AIRTEL CODE:

1. * Airtel to Airtel 15paise Call on 4 selected numbers. Just dial *#110#
2. * To know the Tariff Validity *131#
3. * To know the A/C manage Menu *121#
4. * To know the HelloTunes Menu *678#
5. * To know ur Balance *123*1#
6. * To know Local A2A Balance *123*3#
7. * To know STD Call Balance *123*6#
8. * To know ISD call balance *123*2# , *123*4# , *123*5# 

NOKIA CODE :

1.  * To Restore Battery Setting *#7780
2. * To Know Manufacture Date *#3283# & *#0000#
3. * To Stop Sim clock *#746025625#
4. * To Stop Operator Logo *#67705646#
5. * To Reset Phone Timer *#73#
6. * To Warranty *#92702689#

SAMSUNG CODE :

1. * To know software version *#9999#
2. * To ReBoot Phone #*3849# & #*2562#
3. * To On/OFF Phone Time #*2558#
4. * To Unlock Phone #*7337#
5. * To On/Off GSM facility #*4760#
6. * To know about Memory & Data *#9998*246#
7. * To know Phone’s Lock status *#7465625#
8. * To Serial No. *#0001#
9. * To Unlock Code No. *2767*637#
10. * To See Free space *#8999*636#
11. * Software Version *#1111#
12. * Firmware Version *#1234#
13. * Hardware Version *#2222#
14. * For Call List *#2255#  

LG CODE :

1. * Go to Phone’s Test Mode 2945#-*#
2. * For Secret Menu 2945*-#01*#
3. * To know software version *8375#
4. * IMEI No. *#06#
5. * To Manage Sim card Lock (For LG7010&LG7020) dial 2945#*70001#
6. * To Manage Sim Lock (For LG B1200) dial 1945#*5101#
7. * To Manage Sim Lock (For LG B5200 & 510w) dial 2945#*5101#
8. * To Manage Sim Lock (For LG 500 & 600) dial 2947#*
9. * IMEI and SW (LG 510): *#07#
10. * Software version (LG B1200): *8375#
11. * Recount cheksum (LG B1200): *6861#
12. * Factory test (B1200): #PWR 668
13. * Simlock menu (LG 7020, 7010): 2945#*70001#

GSM Secret Codes :

1. Type *#61# and press call - Check redirection status.
2. Cancel all redirections: ##002# *43# to activate call waiting, to deactivate #43#.
3. * If your phone doesn't have incoming call barring and outgoing call barring, you can try this.
4. * For outgoing call barring dial *33*barcode*# and pres OK. To deactivate it dial #33#barcode*#.
5. * On any phone on any network type in **43# to enable conference calls. You can make up to 7 calls at once
6. * If you need to block SMS reception (if you are spammed by someone) just press this code: *35*xxxx*16# xxxx is your Call Barring code (default is 0000). To remove this barring type: #35*xxxx#
7. * If you want to hide/show your phone number when calling, put one of these codes below in front of the number that you are going to call.(*#30# / *#31# or *31# / #31# ) Works on some networks.
8. * Typing *0# or *nm# on the beginning of a txt message gives you detailed delivery report on some networks.. But turn off reports in message settings before.
9. * When the sim card-pin blocked type **042*pin2 old*newpin2*newpin2 

Source : http://maayazal.blogspot.in