What happens on the IPhone 4 when you hit emergency call at lock screen?

I'm asking specifically for the iPhone 4 if you don't know then please don't make something up I REA that it prompts a screen for you to place a call and I've also read that is automatically starts calling 911 which is true

When you use the emergency call feature on any phone connected to a network or not it dials 911 and tracks your phone as soon as they answer