Many of you may know already but never is to much remembering.
So here are some codes you can enter in phone keypad.
System info (phone, battery, used and WiFi information)
*#*#4636#*#* (INFO) – Works on all Android devices
Service menu – The classic one that we are used to see from ages on ericsson and sony ericsson phones. (service info, device tests, etc…)
*#*#7378423#*#* (SERVICE)
Demo – Used in stores for demonstration, a video demonstrates the product when we push the power button and acts as a normal phone when we touch it.
*#*#73556673#*#* (sellmore) – choose activate. To deactivate just enter the same code again.
To reboot your phone (because you can’t remove the battery) press and hold at same time the power and volume up keys till it reboot.
SCREENSHOT: Holding down the power button now brings you a different menu compared to Android 2.3.7. Most users will probably notice that the ‘Take screenshot’ option has disappeared. Android ICS now allows you to take screenshots by holding down the power button and volume down button at the same time.