Cell Broadcast Emergency Alerts being tested in the UK
mobile · 5 comments · 700 words · read ~807 times.
I have only been on the periphery of this project - back from when I worked at a Mobile Operator - so it's incredibly exciting for me to see this come to life.
This morning, my phone picked up an Emergency Alert test from the Cell Broadcast system.
I had to specifically opt-in to receive test messages. Each phone is different, but on Android I unlocked developer options and found the alerts settings within notifications. Your phone will almost certainly have the option somewhere else.
How does this work?
The mobile phone network is broadcast from antennae. Each antenna covers a physical area. This area is called a "cell". Each cell has an ID. The network knows where each antenna is physically located. So the network knows where you are based on which antenna you are connected to.
It is, of course, a lot more complicated than that. But that's pretty much all you need to know for now.
When someone calls or texts you, the antenna broadcasts a message which says "Hey, is there a device with phone number 1234 here?" All phones in the area can hear this message, but they only respond if the message is for them.
Again, it is a lot more complicated in reality - but the basics are that each cell can broadcast messages which every device in area can receive.
Back in the olden days, this was used to show phones which area code they were in. It used to be cheaper to call a landline phone when you were physically close to it. Weird!
There were plans to use it for targetted location-based advertising - walk into a shopping mall and get a pop-up with deals - but that never took off, thankfully!
Evolution
Cell Broadcast hasn't changed much in the last few decades. A mobile operator can send a message to a specific geographic area. It can also set the category of message as well. This is used in places like the USA for their emergency alerts - which covers things like weather warnings, missing children, and incoming missile attacks.
In the UK, it appears flood alerts are being trialled. And, I suppose, other types of alerts might follow depending on how successful the trials are. I'm not involved in them and have no insider knowledge.
What it looks like
Alerts can be set to have an alarm tone
Thanks
Huge congratuations to all the people who have worked so hard to get this up and running. The future's bright, eh?
1UP & on to the next level. #CellBroadcast #EmergencyAlerts pic.x.com/dpnychn6pg
Feedback
One of the drawbacks of testing an emergency alert is that it generates some "robust" feedback!
Anyone else rudely awakened at 07:45h by @O2 emergency alert test?!? An automated voice saying Asterix Asterix Asterix This is an emergency alert test etc etc etc #O2 #EmergencyAlert #O2EmergencyAlert #FuckYouO2 pic.x.com/bndvwhjqfv
Lee says:
Does anyone know how to switch on the test for the iPhone. Apple specifies
500525371#to switch US emergency alert tests on for the US - is this the same for the UK?https://support.apple.com/en-gb/HT202743
Yes, the Cell Broadcast channel is the same. It's standard.
Having had a few go off in the middle of the night in New York and Tokyo I can attest they’re flipping loud. Slept through a (smallish) earthquake, only to be woken up by two blaring phones telling me to stay where I was!
I received one in the middle of the night when I was in Japan last year. I was really confused by why there was a siren going off!
@Edent @bazbt3 @revk @Br3nda I experienced a cellular emergency broadcast while in Amsterdam last summer for a major fire. I wondered what my phone was up to at first as it was set on silent!