On the main screen, type:

[Device Related]:

*#06# — IMEI number
*#0001# — Serial number
*#232337# — Bluetooth MAC Address
#*3888# — Bluetooth Test mode
*#9999# — Software version
*#0837# — Software version
*#1111# — Software Version
*#8999*837# — Hardware version
*#2222# — Hardware Version
*#1234# — Firmware Version
*#5282837# — Java Version
*#8999*8376263# — All Versions Together
#*#8377466# — Software Version & Hardware Version

*#8999*636# — Storage capacity
*#9998*246# — Battery status- Memory capacity
*#0228# or *#8999*228# — Battery info
#*7983# — Voltage/Freq
#*7986# — Voltage
#*2286# — Databattery
#*2474# — Charging Duration

*#0523# - *#8999*523# — Display contrast
*#9998*523# — LCD contrast
*#8999*523# — LCD Brightness
#*7666# — White Screen

*#8999*782# — Show date and alarm clock
#*2558# — Time ON
#*8466# — Old Time

*#8999*8378# — Test Menu
*#9998*842# - *#8999*842# — Vibration test
*#9998*289# - *#8999*289# — Alarm beeper - Ringtone test
*#9998*324# - *#8999*324# — Debug screen
*#8999*377# — Error LOG Menu
*#8999*327# — EEP Menu
*#8999*667# — Debug Mode
#*5737425# — Java Mode
*#8999*786# — The display during warning
*#92782# — PhoneModel (Wap)

*2767*3855# — Full Reset
*2767*2878# — Custom Reset
*2767*927# — Wap Reset
*2767*226372# — Camera Reset (deletes photos)
*2767*688# — Reset Mobile TV
#7263867# — RAM Dump (On or Off)
#*7828# — Task screen
#*2562# — Restarts Phone
#*2565# — No Blocking? General Defense.
#*3353# — General Defense, Code Erased.
#*3837# — Phone Hangs on White screen.
#*3849# — Restarts Phone
#*7337# — Restarts Phone (Resets Wap Settings)
#*5376# — Delete all SMS
#*3676# — Format Flash Volume

*#9125# — Smiley
*#2255# — Call List
#*2886# — AutoAnswer ON/OFF
#*2255# — Call Failed
#*7693# — Sleep Deactivate/Activate
#*2679# — Copycat feature Activa/Deactivate
#*4263# — Handsfree mode Activate/Deactivate

#*2775# — Switch to 2 inner speaker
#*7200# — Tone Generator Mute
#*2834# — Audio Path (Handsfree)
#*3270# — DCS Support Activate/Deactivate
#*3282# — Data Activate/Deactivate
#*7326# — Accessory
#*22671# — AMR REC START
#*22672# — Stop AMR REC
#*22673# — Pause REC
#*22674# — Resume REC
#*22675# — AMR Playback
#*22676# — AMR Stop Play
#*22677# — Pause Play
#*22678# — Resume Play
#*77261# — PCM Rec Req
#*77262# — Stop PCM Rec
#*77263# — PCM Playback
#*77264# — PCM Stop Play
#*22679# — AMR Get Time

[Network Related]:

*#8999*778# — Display SIM card information
#*7462# — SIM Phase
*#8999*638# — Show network information
*#8999*9266# — Display received channel number and received intensity
*#4777*8665# — GPSR Tool
#*7288# — GPRS Detached/Attached
#*7287# — GPRS Attached
#*2527# — GPRS switching set to (Class 4, 8, 9, 10)
#*3940# — External looptest 9600 bps
#*3941# — External looptest 115200 bps
#*4760# — GSM Activate/Deactivate
#*3476# — EGSM Activate/Deactivate
#*3273# — EGPRS multislot (Class 4, 8, 9, 10)
#*2077# — GPRS Switch
#*2027# — GPRS Switch
#*0227# — GPRS Switch
#*0277# — GPRS Switch

*#7465625# — Check the phone lock status
*7465625*638*Code# — Enables Network lock
#7465625*638*Code# — Disables Network lock
*7465625*28638# — Auto Network lock ON
#7465625*28638# — Auto Network lock OFF
*7465625*746*Code# — Enables SIM lock
#7465625*746*Code# — Disables SIM lock
*7465625*28746# — Auto SIM lock ON
#7465625*28746# — Auto SIM lock OFF

Type in *#0000# on a Samsung A300 to reset the language
Master reset(unlock) #*7337# (for the new samsungs E700 x600 but not E710)
Samsung E700 type *#2255# to show secret call log (not tested)
Samsung A300, A800 phone unlock enter this *2767*637#
Samsung V200, S100, S300 phone unlock : *2767*782257378#

Type *#9998*627837793# Go to the ‘my parameters’ and there you will find new menu where you can unlock phone.(not tested-for samsung C100)
To unlock a Samsung turn the phone off take the sim card and type the following code *#pw+15853649247w#
Java status code: #*53696# (Samsung X600)

If you want to unlock your phone put a sim from another company then type *#9998*3323# it will reset your phone. Push exit and then push 7, it will reset again. Put your other sim in and it will say sim lock, type in 00000000 then it should be unlocked. Type in *0141# then the green call button and it’s unlocked to all networks. This code may not work on the older phones and some of the newer phones. If it doesn’t work you will have to reset your phone without a sim in it by typing *#2767*2878# or *#9998*3855# (not tested)