system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: How does calling 911 work in terms of connecting you to your closest 911 center?
gpt
The emergency 911 call is routed to the local call center based on the origin location of the calling party. If it was from a landline then there is obviously a registered address where that phone is calling from, but if it is a cell phone then it is determined by the location of the cell tower. Since such towers generally have a range of about 5 miles (conceptually longer but on average they are within 5) this is a reasonably accurate estimate of the caller's location. If it happens the address of the emergency is just over the line to a different 911 center's territory they can quickly and easily transfer the call to that other center.