SECRET CODE SAMSUNG PHONE

*#*#4636#*#*                               : phone information
*2767*3855#                                : hard reset *
*#*#7780#*#*                               : factory reset **
*#*#7594#*#*                               : change end call / power option
*#*#197328640#*#*                     : service mode
*#*#273283*255*663282*#*#*    : screen copy files (backups of media files)
*#*#526#*#*                                 : wlan test
*#*#232338#*#*                           : shows the wifi mac address
*#*#1472365#*#*                         : gps test
*#*#1575#*#*                               : another test gps
*#*#232331#*#*                           : bluetooth test
*#*#232337#*#*                           : shows the bluetooth device address
*#*#8255#*#*                               ; gtalk service monitor

Various launch codes to factory tests:
*#*#0283#*#*                               : packet loopback
*#*#0*#*#*                                    : lcd test
*#*#0673#*#*                               : melody test
*#*#0842#*#*                               : device tests (vibration tests and backlight test)
*#*#2663#*#*                               : touch screen version
*#*#2664#*#*                               : touch screen test
*#*#0588#*#*                               : proximity sensor test
*#*#3264#*#*                               : ram version

codes to get the firmware version information:
*#*#4986*2650468#*#*               : pda, phone, h / w, rfcalldate
*#*#1234#*#*                               : pda and phone
*#*#1111#*#*                                : FTA sw version
*#*#2222#*#*                               : FTA hw version
*#*#44336#*#*                             : pda, phone, csc, build time, changelist number


NOTE :
Hard reset deletes all files and settings in internal memory, or equal to reformat the firmware warning! If it is a direct push hardreset, there is no cancel option.
Factory reset just delete the account, system & application settings