Public emergency alerts to be sent to all UK smartphones on 23rd April

Grey_Critic

*** And what would those who actually got a 4 minute warning of becoming toast do? ***

PANIC

powerful_Rogue

victor2 said:

Nelliegrace said:

So much for modern technology.

In the 1950’s and 60’s one landline call summoned the members of the Civil Defence to report immediately for a crisis. 

The basic WW2 sirens could be heard for up to 25 miles. 
We had a four minute warning system covering the whole country for a nuclear attack. 

With a gap of several minutes between the best and second best phone message, and millions of people not getting the message, it seems that most of us would be toast. 

And what would those who actually got a 4 minute warning of becoming toast do? 

Make love with the wife at least 4 times.

Sarahspangles

Nelliegrace said:

So much for modern technology.

In the 1950’s and 60’s one landline call summoned the members of the Civil Defence to report immediately for a crisis. 

The basic WW2 sirens could be heard for up to 25 miles. 
We had a four minute warning system covering the whole country for a nuclear attack. 

With a gap of several minutes between the best and second best phone message, and millions of people not getting the message, it seems that most of us would be toast. 

I detect sarcasm but the advantage with the phone alerts that are being tested is that they can be pushed out to a predictable area, and accompanied by defined information.  Other siren systems are less targeted.

[Deleted User]

Nelliegrace said:

So much for modern technology.

In the 1950’s and 60’s one landline call summoned the members of the Civil Defence to report immediately for a crisis. 

The basic WW2 sirens could be heard for up to 25 miles. 

So I hear a Siren what do I do, stay in the house and get under the table to survive a bomb or leave the house and run to high ground to avoid a Tsunami?

What do hearing-impaired people do if they don't hear the siren?

facade

savergrant said:

If a phone doesn't have a sim in it surely it could only receive incoming messages through a WiFi connection? As the sim is the phone's connection to the cellular network.

On my dual sim phone both sims are set to always active, so I can receive a call on either number at any time. Will have to try using family phones and call both numbers (near) simultaneously.

If there are a series of tests, I'll try mine out SIMless, I did want someone here to remove their SIM and see if they got the alert..

The phone will still make emergency calls with no SIM, so it can connect to a tower, it just cannot use paid for services.

Mine shows the signal strength and says NO SERVICE where it normally says Tesco without a SIM, (and emergency calls only).

I don't know enough about cellular technology, but I'm guessing the phone announces itself with its IMEI number, but cannot authorise access to paid for services without a registered SIM.

No-one is saying exactly how it works, if it went to the 'phone and ignored the carrier, then the people on Three would have got it.

[Deleted User]

facade said:

savergrant said:

If a phone doesn't have a sim in it surely it could only receive incoming messages through a WiFi connection? As the sim is the phone's connection to the cellular network.

On my dual sim phone both sims are set to always active, so I can receive a call on either number at any time. Will have to try using family phones and call both numbers (near) simultaneously.

If there are a series of tests, I'll try mine out SIMless, I did want someone here to remove their SIM and see if they got the alert..

The phone will still make emergency calls with no SIM, so it can connect to a tower, it just cannot use paid for services.

Mine shows the signal strength and says NO SERVICE where it normally says Tesco without a SIM, (and emergency calls only).

I don't know enough about cellular technology, but I'm guessing the phone announces itself with its IMEI number, but cannot authorise access to paid for services without a registered SIM.

No-one is saying exactly how it works, if it went to the 'phone and ignored the carrier, then the people on Three would have got it.

You will no receive emergency alerts without a SIM card - just like those connected to 2G/3G didn't get the alert - only phones connected to 4G/5G at the time of the alert received it (except for some technical errors)

With no SIM card, the emergency calls feature doesn't mean you are connected to any network at all - the signal strength you see is just an indication of how strong it is receiving the nearest network but it is not communicating back to the network at all. The phone does not announce itself to the network without a SIM.

When you dial a recognised emergency number, eg 999 in the UK, the phone will connect to the strongest network (if any) and place the call. The phone is otherwise not connected to a network and therefore cannot receive any alert.

flaneurs_lobster

facade said:

savergrant said:

If a phone doesn't have a sim in it surely it could only receive incoming messages through a WiFi connection? As the sim is the phone's connection to the cellular network.

On my dual sim phone both sims are set to always active, so I can receive a call on either number at any time. Will have to try using family phones and call both numbers (near) simultaneously.

If there are a series of tests, I'll try mine out SIMless, I did want someone here to remove their SIM and see if they got the alert..

The phone will still make emergency calls with no SIM, so it can connect to a tower, it just cannot use paid for services.

Mine shows the signal strength and says NO SERVICE where it normally says Tesco without a SIM, (and emergency calls only).

I don't know enough about cellular technology, but I'm guessing the phone announces itself with its IMEI number, but cannot authorise access to paid for services without a registered SIM.

No-one is saying exactly how it works, if it went to the 'phone and ignored the carrier, then the people on Three would have got it.

I had assumed that a SIM-less phone would receive the alert but then read in a proper newspaper and on the BBC website that removing the SIM from a phone was one way to prevent the alert.

My dual SIM phone only received 1 alert although both SIMs are active for calls/SMS/data. So yes, I'd like to know how it works too.

Is it being kept rather opaque for security reasons or is there a technical description somewhere?

[Deleted User]

flaneurs_lobster said:

facade said:

savergrant said:

If a phone doesn't have a sim in it surely it could only receive incoming messages through a WiFi connection? As the sim is the phone's connection to the cellular network.

On my dual sim phone both sims are set to always active, so I can receive a call on either number at any time. Will have to try using family phones and call both numbers (near) simultaneously.

If there are a series of tests, I'll try mine out SIMless, I did want someone here to remove their SIM and see if they got the alert..

The phone will still make emergency calls with no SIM, so it can connect to a tower, it just cannot use paid for services.

Mine shows the signal strength and says NO SERVICE where it normally says Tesco without a SIM, (and emergency calls only).

I don't know enough about cellular technology, but I'm guessing the phone announces itself with its IMEI number, but cannot authorise access to paid for services without a registered SIM.

No-one is saying exactly how it works, if it went to the 'phone and ignored the carrier, then the people on Three would have got it.

I had assumed that a SIM-less phone would receive the alert but then read in a proper newspaper and on the BBC website that removing the SIM from a phone was one way to prevent the alert.

My dual SIM phone only received 1 alert although both SIMs are active for calls/SMS/data. So yes, I'd like to know how it works too.

Is it being kept rather opaque for security reasons or is there a technical description somewhere?

It is quite simple, the data connection is only available from one SIM at a time - ie the 4G/5G and the other SIM will use the 2G network for calls / SMS only. Normally you pick this in the mobile data settings on the phone.

So only one of you SIM's met the criteria of being connected to 4G/5G during the test.

savergrant

My data connection was switched off. I received one alert.
The phone was connected to home WiFi, but not through either sim. I am sure Google has previously sent notifications to my old phone which didn't have a sim in it at the time. It now had a lebara sim as an emergency backup sadly or it might have given useful insight.

[Deleted User]

savergrant said:

My data connection was switched off. I received one alert.
The phone was connected to home WiFi, but not through either sim. I am sure Google has previously sent notifications to my old phone which didn't have a sim in it at the time. It now had a lebara sim as an emergency backup sadly or it might have given useful insight.

One of your SIM cards must have had a 4G/5G connection to receive the alert - the alerts were not sent via the Internet whatsoever.

Getting Google notifications on a phone with no SIM is not comparable, they are push notifications sent via the internet and only require wifi connectivity.