Yahoo News explains: What you need to know about Trump’s nationwide test alert

For the first time ever, on Oct. 3, Americans nationwide will receive an alert from the president on their cellphones. It’s an emergency test message, as part of the Federal Emergency Management Agency’s system to warn the entire nation in the event of a national emergency. It could include alerts of terrorist threats or natural disasters.

The test was originally supposed to be tried out on Sept. 20, but it was delayed due to response efforts for Hurricane Florence.

Since 2012, government agencies have issued more than 40,000 emergency alerts to cellphones, but they only targeted specific regions.

Here’s what you need to know about the test.

The presidential alert will be sent out at 2:18 p.m. ET on Wed., Oct. 3. The header will read “Presidential Alert” and the message will say, “THIS IS A TEST of the National Wireless Emergency Alert System. No action is needed.” The test will set off the same loud sound used for other alerts.

The majority of cellphone users will receive the alert if the device is turned on, the phone has service, and the wireless provider is part of the Wireless Emergency Alerts system. No one can opt out of the alerts.

Two minutes after the cellphone test, FEMA will also run a test of its Emergency Alert System for radio and television broadcasters.

By law, FEMA is required by law to conduct a nationwide test of its public alert systems no less than once every three years.