3, Emergency situations
All mobile phones in the world can dial 112, the common emergency rescue number. If you find that the area where you are located has no mobile phone signal coverage and you have run into an emergency situation, you can always make a call to 112, because at this moment your mobile phone will automatically search all available networks and set up an emergency call. Interestingly enough, even if your mobile phone is in key lock status, you can still dial 112. Try it!