I'll soon be rich. Going to build an app that detects from your gps/cell triangulation which dispatch to direct your 911 call to. Can't be that hard. Sort of surprising the authorities have not had it done already in view that 911 can be a life or death call.
Already done. Kinda. Doesn’t always work.
Having built a couple of similar telecom systems and also having worked on the other side of the headset in the days before E911, when all we had was a blinking light and no caller ID/ANI info, or address/georeferencing info, and we had to ask where you were, or get the phone company to trace the call... and they wouldn’t trace calls after-hours, so if you couldn’t talk, you were probably going to bleed out... unless we could get you to describe some landmarks...
Let’s just say there’s a lot of things that can go wrong in an E911 call route from a cell phone. But things have gotten a LOT better since I was an intern Sheriff’a dispatcher.
Not the least of which is simply crossing jurisdictional boundaries if you’re moving. I once chased a drunk driver (I shouldn’t have, but I was ****ed. He ran over the right front bumper of our Honda Accord at 60 MPH on the highway with his lifted truck. I was amazed he didn’t kill us all, right then...) through five jurisdictions. Got transferred five times during the call. He got away.
But remember, your phone call may be being handled by a cell site a few miles from where you are. And the GPS data in your smartphone is not sent in any meaningful way to the dispatch center usually. It’s usually only AGPS from the network, which is an estimate of your position in relation to the cell sites that hear your phone the best, and that’s a constantly changing thing. It only works with any consistency or accuracy when you’re not moving. Newer phones can embed their location into the call control data stream but not all dispatch facilities have any way to receive or display it.
The stuff to do that is hideously expensive. You don’t want to know how expensive.
The initial “hang up” was probably the network routing you to one dispatch facility by location and then a call drop. The network is programmed to try to NOT drop a 911 call, as is your phone, so the next tower probably auto-connected you to its pre-programmed dispatch center during a bad call handoff between the two towers.
The phone and the network will try a lot harder to connect an emergency call than a non-emergency one nowadays. Higher timeouts on bad signal, holding the phone in an off-hook status longer, more power to the frequency your phone is on at the detriment of dropping other calls, telling the phone to go to higher power on its transmitter, etc.
Problem is, you’re mixing cell routing with oddball call routing. For you the end user, you dial one number. The network has to e programmed behind the scenes that “911” goes to all sorts of different actual routing numbers you don’t dial.
Life-Safety stuff is engineered very carefully and tested by more than one person, unlike almost everything else in telecom. But I’ve seen a typo mess up call routing for a telecom system that tracked lost military nuclear materials, and also seen one mis-set clock source nearly scrub a missile test at White Sands. Human error still lurks in the settings.
Telecom is a mess on wireline. Doing it over tiny pocket radios only makes it worse. I’m somewhat amazed it works at all, really.
