Android Secret OR Security Keys

About your phone and battery-*#*#4636#*#*
Factory data reset-*#*#7780#*#*
About phone camera-*#*#34971539#*#*
End Call / Power"-*#*#7594#*#*
WLAN, GPS and Bluetooth Test Codes-*#*#232339#*#*
#*#232338#*#* - Shows WiFi MAC address
*#*#1472365#*#* - GPS test
*#*#1575#*#* - Another GPS test
*#*#232331#*#* - Bluetooth test
*#*#232337#*# - Shows Bluetooth device address
GTalk Service Monitor.*#*#8255#*#*
*#*#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
*#*#0283#*#* - Packet Loopback
*#*#0*#*#* - LCD test
*#*#0673#*#* OR *#*#0289#*#* - Melody test
*#*#0842#*#* - Device test (Vibration test and BackLight test)
*#*#2663#*#* - Touch screen version
*#*#2664#*#* - Touch screen test
*#*#0588#*#* - Proximity sensor test
*#*#3264#*#* - RAM version