This is a test. This is only a test. But get ready for it anyway. 

On Wednesday, the whole nation will be put on alert. But don’t panic – it’s only a test. 

At 2:20 P.M. Eastern Time, warning alarms will sound on all cell phones, TVs, and radios across the United States. 

It’s all part of a nationwide emergency alert test. 

Wednesday’s alarm will be followed by the message: “This is a test of the National Wireless Emergency Alert System. No action is needed.”

Tests like this are done every three years to ensure all systems are working properly.