President Donald Trump, via the Federal Emergency Management Agency, will send out an alert to phones across the nation Wednesday afternoon in the first-ever test of the presidential emergency alert system.

All modern cell phones that have signal should receive the alert, including an audible tone and buzzing, at 2:18 PM EST, and there is no way to opt out (you can turn your phone off, of course, but the alert will come through when you power it on again). The alert will also scroll across TVs and be transmitted over the radio. Originally, the test was scheduled to happen in September, but with some areas receiving real alerts due to Hurricane Florence, FEMA decided to postpone it until October.

The Integrated Public Alert and Warning System is FEMA’s method of spreading the word of emergency reports. It already sends out local alerts such as reports of missing children and weather emergencies, but the presidential alert tested Wednesday is reserved for major emergencies that affect the entire nation, like a widespread weather, health, or security issue. It was developed after former President Barack Obama signed a law in 2016 expanding the nation’s emergency alert systems.

At this point, we’re used to Trump sharing his every thought with the nation via Twitter, and many people joke that giving the president access to a system that floods more than 225 million cell phones with an instant alert is asking for trouble. Others joke about what the message might say with Trump behind the keyboard:

However, FEMA has already released the text of the message, which is pretty straightforward: “THIS IS A TEST of the National Wireless Emergency Alert System. No action is needed.” It also clarified that the alerts, in a real situation, would be sent out by direction of the president, but the president himself won’t be writing the messages.