(also note it will use any available cell tower operated by any provider and will preempt normal calls if the station is too busy, so the appearance of no signal/"bars" shouldn't discourage trying to call 911)
> Even without Sim card.
Depends on the countries though. A sim card (whether expired or not) is needed in France to call 112
To be pedantic: the cell phone is required to have this capability - the network just doesn't have to accept it.