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Are you saying the phone sends some type of flag "emergency call" rather than the actual dialed digits? The interesting implication of this is if I'm travellin
by gregmac 7y ago
Are you saying the phone sends some type of flag "emergency call" rather than the actual dialed digits?
The interesting implication of this is if I'm travelling in a country with another emergency number, I can "dial" the one from my home country (which is really just the sequence to initiate "emergency call") and be connected to local services.
I can see some references to 911 working on the UK phone system where the emergency number is 999 -- but this seems to be a separate mechanism (the phone company explicitly routes this number, as well as the EU emergency number 112).
- goodcanadian 7y agoYes, that is my understanding. Dialling 911, 999, 112, or 000 on your mobile phone will all work regardless of where you are.
- OrangeMango 7y agoYes, that is exactly what happened back then: it was in the ratified spec. I can't believe that newer systems would be any different.
- xxpor 7y agoI've explicitly dialed 112 (when I actually had a reason to call 911) just to see if it worked. It worked perfectly fine.
- lostlogin 7y agoI laughed. Your thought process at that time would be interesting to see written down.
- xxpor 7y agoIt was certainly one of those situations that if the Seattle Police had a non-emergency number that they actually wanted you to use I'd have used that instead.
- anticensor 7y agoDedicated police call numbers are always routed via regular infrastructure.
- bitwize 7y agoWhat about 01189998819991197253?
- tialaramex 7y agoThis will only work if you are currently inside a Channel 4 TV show. It is very important to remember that last "three".
- bitwize 7y agoWell, it does trigger an easter egg in later versions of Android...
- grecy 7y agoIt's also why you can possibly make an emergency call when your phone has no bars of signal displayed and won't make a regular call. It will connect an emergency call even if the quality is well below the standards for a normal voice call.
- grawprog 7y agoCan confirm 999 also works in Canada after an embarrassing pocket dial in which I had to explain to the authorities I was not being threatened or under duress and it was in fact just an accident.
- feikname 7y agoI believe it's not the phone that flags it as an emergency call, but the transmission tower, which has a "hardcoded" list of the emergency numbers.
- kevin_nisbet 7y agoThis is incorrect. When I worked on LTE networks, I did work on a few problems with VoLTE based 911 service, although I didn't specialize in 911 services. In many ways, something like an LTE tower doesn't really know what a phone call is. It just looks like packet data. So there are several fields in the signalling, that indicate that a request is related to an emergency, which should have emergency handling. This can include things like dropping other lower priority traffic, prioritizing the packets themselves on the network, etc. But the other interesting thing is in VoLTE, you actually do a new IP assignment (to an sos PDN) specifically for the emergency call, so you have a sort of new registration to the network. This allows you to make an emergency call on any network that is available. Although scanning for an available network can take some time, so you'll likely use your own carrier if they're currently available. Note: I've been out of the industry a few years now, and specific to emergency calls only have knowledge specific to LTE and UMTS.