Did your emergency alarm not go off on your mobile phone? Here are the reasons why.

BarcelonaThis Monday at 10:00 AM, the phones of more than five million people rang simultaneously. Civil Protection sent a mass alert as part of an emergency drill to all mobile phones with coverage and connected to antennas in the Barcelonès, Baix Llobregat, Maresme, Vallès Oriental, and Vallès Occidental regions. This meant that it affected everyone in this area, including those passing through on the road or using public transport at the time of activation.

But what should you do if you haven't received this alert? Contrary to what's being circulated on social media, These emergency alerts on your mobile phone cannot be deactivated.As technology journalist Albert Cuesta recalled in several articles published in ARA.

Unlike conventional SMS messages, which are sent to individual phone numbers and can be answered directly, ES-Alert – like its counterpart systems in other states –It sends one-way messages to terminals of any operator....even from other countries, which are under the coverage of a specific antenna or group of antennas at a given time. ES-Alert alerts are activated by default on all compatible phones, that is, those with Android versions later than 11 (including all the customization layers added by Chinese and Korean phone brands, such as Samsung's One UI or Xiaomi's MIUI). 15.6.

This system, mandatory in all member states of the European Union,It is the Spanish version of Cell Broadcast technology(CB), integrated into the GSM standard since the second generation (2G) of mobile telephony. It includes three alert levels: Level 2 is used to disseminate advice and pre-alerts, and Level 3 is used to request public assistance in cases such as a missing child. These optional deactivation operations only affect these two levels, which ES-Alert does not use. Level 1, reserved for imminent emergencies, can only be deactivated by turning off the phone until the alert situation has passed, which would be frankly imprudent.

So why hasn't the alert reached some phones? There could be several reasons, as Cuesta points out. The first, and least likely, is that the phone is older than the versions mentioned. It could also be turned off, or even broken. But the most likely reason for not receiving the ES-Alert message is that the phone isn't actually connected to the mobile operator via the cellular network, but rather via the internet using the VoWiFi function (also known as Wi-Fi Calling), which allows you to make and receive calls even in places without mobile coverage, such as basements and garages.

What was the alert like?

The ES-Alert system is only used for drills—to familiarize the public with the tool—and when there is an imminent danger to human life. The message content varies depending on whether there is a fire nearby requiring shelter in place, if heavy rain is forecast and outdoor activities are discouraged, or if there has been an accident that could cause a chemical cloud, among other things. This state-run system—the Catalan government has no authority to make changes—sends pop-up messages to all mobile phones within a specific antenna coverage area. In this case, the message that appeared on screens this Monday was: "Civil Protection alert test by the Government of Catalonia. In a real emergency, you would receive instructions on how to protect yourself." The text was sent in Catalan, Spanish, and English and was accompanied by the distinctive, loud ES-Alert warning sound. The aim of the drill is to verify that this warning system functions correctly and that, in the event of a real emergency, catastrophe, or serious accident, the channel allows for immediate instructions to be given to the public. However, it has already been made available to the public. an online survey where users can anonymously indicate whether the alert was received correctly, in what language, and with which telephone company, in order to evaluate its performance.

"It's a delivery system that gives us great coverage quickly. One of our functions is to warn the public about risks that may affect them, and in a serious risk situation, it has proven its usefulness in delivering our warnings, orders, and recommendations," the Director of Civil Protection of the Generalitat recently stated.

**We have corrected this news item because Level 1 alerts sent via ES-Alert cannot be deactivated on mobile phones.