The most common these days is the wireless or “cell” phone. These are the worst for “911” to track. Modern cell phones will attempt to communicate their location to the “911 center” where the call is coming from. It rarely gives an accurate location immediately. In fact sometimes it takes oh, maybe a minute to show a decent location. On our “911” computer screen it will actually show a cell phone tower “address” you are calling from, but what we are really looking at is a map where the system tries to “plot” where the caller is. It’s of course rarely next to a cell tower. It also gives a percentage of how accurate it thinks the plotted location is, and a distance from the center of that location. So it might say it’s 90 percent sure the caller is within 5 meters of the location plotted on the map. It might say its only 70 percent sure that the location is within 1600 meters of the location plotted (not too much use if you expect us to know what house you’re in in an urban environment). We can ask the “system” to retry the mapping, and often after a few seconds we can narrow down the location, often to just a car length or so. Since people call from near jurisdictional boundaries (and are sometimes driving thru different jurisdictions) the wrong PSAP (public safety answering point, proper name for place that receives 911 calls) often gets the call. It is usually an easy matter to directly transfer these calls to the proper PSAP if its adjacent to the one is was misrouted to. This happens many times. Maybe you exit the freeway and call “911” about a traffic accident on the freeway. Likely the local police dept will get the call and have to transfer the call to the highway patrol or state police who police the freeway. Maybe you are calling from a business that is right next to a major freeway..The highway patrol may get the call and have to transfer the call to the correct PD. You get the idea. Anyway, technology has improved but don’t assume a 911 call taker will instantly know where you are calling from if you are using a wireless phone.