how emergency call works (technically) ?

need to know more about how the emergency call happened because even if you have not a SIM card in your mobile phone the call will delivered .
how the nearest antennas deals with the request from your mobile phone 
that's all .
thanks for concerning ......

Actually the process if fairly simple:

The network needs to identify the phone for a call and of course for the billing.

This identification happens through your Sim card.

Certain numbers, like 000, 911, 110 or 112 are addressed as emergency numbers with no requirement for identification of the network provider.

So when you call these numbers without a Sim card the network simply transfers the call to the corresponding operator or emergency system.

Since no identification is required the phone is set to be able to dial those numbers even without a Sim card.

The strongest network that is supported by the phone and in reach will be used to establish the connection.

The complete technical bit is slightly more complicated in detail though.

rickharris2 years ago

I don't exactly know and don't see much useful information on the web BUT.

reverse engineering what must happen:

The processor in the phone must have 911 set into its structure so you don't need a sim card - not too much of a problem because 911 is an emergency number used almost all over the world, even in the UK where out normal emergency number is 999, 911 will also work.

The phone call will be routed by the cell system in much the same way any pother call is routed so that it ends up at the emergency call centre for your area.

The call centre can locate the 2 or 3 closest cell towers to your phone and can therefore narrow the location down to a relatively small area if your in an urban situation with lots of cell towers.

+1

Here too