Where’s my Emergency Alert today?
Today, 22 June 2021, testing of the UK emergency alerts service took place using cell broadcast. A number of articles were published about the testing highlighting this was on Android devices and that Apple phones would be tested on the 29 June. Both these tests were listed on the GOV.UK/Alerts pages.
So why not Apple devices?
Apple is protective of the ‘user experience’ and it’s customers. Android devices in general allow access to lots of different options and customisation — the same applies to emergency alerts. Apple likes to keep things simple and as such does not allow test alerts on publicly available handsets*. This means the options for iPhone users on iOS14.5 are simple….opt out or opt back in (the options are automatically on).
*From memory there are two exceptions — Lithuania and Taiwan
Engineering handsets e.g. those that are supplied to the mobile network operator technical teams do have access to test channels on iPhones but the public will not have the option shown here.
Choice of channels
There are three types of test channels. For those keen to know more, these are documented here (p.45 onwards) in the ETSI technical spec and are defined in the 3GPP standards.
The three are channel 4380 (monthly test), 4381 (Exercise) and 4382 (Operator).
The first two may be described differently depending on your handset. In this example, a user can opt in to monthly tests (4380) and operator (4382).
and…in this example a user can opt in to monthly tests (4380), exercise (4381) and operator tests (4382).
Some phones need developer options enabled to get access to the test channels, other phones it is possible to manually add in channels. Ricardo José Saraiva tweets here how this can be done on a Xiaomi handset. Basically…..it’s complicated and you can see why Apple keep things simple.
So…in order to have received an test emergency alert today you would have needed to have an Android device opted in to the right channel (operator alerts) have a 4G or 5G signal, be in an area where a test message was broadcast, be with the right operator testing in that location and be in the area for the duration of the test which could have been broadcast for 5 minutes or less within the window of 1pm-2pm.
As the GOV.UK/Alerts page suggested:
So what about the test on the 29 June?
Forget everything about the test channels. This test planned for Reading is on the live channels….which one is TBC. This is also complex but in order to keep it simple, there’s three main types. Firstly ‘Severe’ — an example here from channel 4373 which is a combination of Severity, Urgency and Certainty. These values are defined in the Common Alerting Protocol (CAP), an international standard for exchanging emergency messages. Earlier in 2020, Simon Nebesnuick and I put forward a standards challenge to adopt this as a UK standard. A video in this tweet shows an emergency alert being received on a Severe channel.
The second type is ‘Extreme’ example here as 4371 that again is based on the Urgency, Severity and Certainty status in CAP. For both Severe and Extreme a user is able to opt-out of receiving these via their handset.
There are other channel numbers for Extreme and Severe which are based on differing combinations of Urgency, Severity and Certainty.
The final category for the UK is ‘Government Alert’ channel 4370. This is also known as the ‘presidential alert’.
Whilst the channel has been renamed for the UK, many handsets still have default settings and as such will display ‘presidential’ regardless.
It’s important to stress that users cannot opt out of this channel — even if on screen they have opted out of all alerts. In this tweet I show opting out of all alerts and the Government Alert still being received.
Receiving an alert on a live channel is very different to a test channel. With the live channels the Alert will over-ride a users settings, even if manually switched to silent and will play the reserved alert tone full volume. Emergency Alerts also use a reserved vibration and some phones will also read out the alert message.
So on the 29 June in Reading, either Severe, Extreme or Government Alert channel could be used and there is no opt-in required other than being in the ‘right’ location when the broadcast occurs and ensuring your phone is has the latest software and is capable of receiving such broadcasts. As this is on the public channels, this will include Apple devices.
What about other channels?
Finally its worth mentioning that other countries have chosen to adopt additional channels, namely Public Safety and AMBER Alerts (4379) which is more widely known and could be enabled in the future for the UK.
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