How to make an emergency call from mobile phone?

Every GSM phone contains an emergency call service. There are country specific emergency numbers, especially 112 and 911 are the emergency numbers.

The speciality of emergency call is you can dial these numbers even when your key pad is locked.
Secondly, you can connect to a local telephone operator (emergency specialist) even if there is no network.

So, once you are connected to a local telephone operator (emergency specialist), you will be redirected to specific emergency departments like Police, Fire and medical.