A FEMA national alert test will take over phones across the country Wednesday

Double-check when your meetings are Wednesday, or you might face an abrupt interruption.

At 2:20 p.m. Philadelphia time, cell phones nationwide will play a special tone and vibrate. It’s all part of a test for the federal government’s emergency alerts.

The Federal Emergency Management Agency and the Federal Communications Commission announced a test for the nationwide Emergency Alert System and Wireless Emergency Alerts. The point is to make sure that the systems are working properly in case of an actual emergency.

“If you’re a teacher, sorry. If you have an important business meeting, it’s going to get interrupted. And if you repair Ming vases as your job, maybe take a small lunch break,” quipped TikTok user @TallGirl6234, whose short form video briefing users about the test alerts has been shared tens of thousands of times. “If you work night shift, just know this is coming.”

The alert will go out Wednesday at 2:20 p.m. Cell towers will broadcast the test for about 30 minutes — but your phone should receive the message only once, and the alert can be turned off once received. Cell phones that are turned on and within range of active cell towers should receive the message simultaneously.

Along with the “unique tone” and vibrations, phones will have a message that says “THIS IS A TEST of the National Wireless Emergency Alert System. No action is needed.” Phones set to Spanish will display: “ESTA ES UNA PRUEBA del Sistema Nacional de Alerta de Emergencia. No se necesita acción.”

On TVs and radios, a similar message will appear. According to FEMA, it will be similar to the regular monthly Emergency Alert System messaging that says, “This is a nationwide test of the Emergency Alert System, issued by the Federal Emergency Management Agency, covering the United States from 14:20 to 14:50 hours ET. This is only a test. No action is required by the public.”

The alert’s backup testing date — which could be prompted by a nationally widespread event, such as severe weather — is Wednesday, Oct. 11.

Yes. This will be the seventh nationwide Emergency Alert Systems test on radios and televisions.

However, it’s only the second time the test has been transmitted to all cellular devices. The first time was in 2018.

Probably not, unless you turn your phone off completely.

Some wireless carriers and phones have the ability to block some alerts, including Amber alerts, public safety alerts, and test alerts.

But according to the Federal Communications Commission, national alerts can’t be blocked. Even in cases in which an alert can be blocked, the FCC recommends keeping alerts on for safety.

As noted by Mashable, the inability to opt-out of emergency alerts can be unsafe for people using hidden cell phones — such as people in unsafe domestic circumstances. But because people know when this alert is scheduled, those trying to avoid the alert can turn their phone off ahead of time.

Yes. Online, a claim has been floating around that the signal broadcast would activate nanoparticles administered through the COVID-19 vaccine into people’s bodies.

The false theory launched on Instagram and claimed that the vaccines contain an ingredient they don’t actually have. Further, high-frequency signals can’t activate any of the COVID-19 vaccines’ actual ingredients, according to PolitiFact.

While the original Instagram post has been taken down for violating Meta policies, other versions have been reposted across social media. A spokesperson for FEMA told the Associated Press that there are no known adverse health effects from the signal and that the sound used in the alerts is the same tone that’s been used since the 1960s.