TAMPA, Fla. (WFLA) — Millions of devices across America will sound off in unison as FEMA conducts another round of nationwide tests of its Emergency Alert System.

The national test will go out to all consumer cell phones, radios, and televisions beginning Wednesday, Oct. 4 at 2:20 p.m. ET.

The alert will mark the third nationwide test, but the second test sent to all cellular devices.

What can you expect?

If you own a cellphone or other device with wireless capabilities, the message that appears on your screen will read: “THIS IS A TEST of the National Wireless Emergency Alert System. No action is needed.”

The test message will display in either English or in Spanish, depending on the language settings of the device. Phones with the main menu set to Spanish will display: “ESTA ES UNA PRUEBA del Sistema Nacional de Alerta de Emergencia. No se necesita acción.”

A test message will also be broadcast to all radios and televisions. This will be the seventh nationwide EAS test.

The message will be similar to the regular monthly EAS test messages the public may be familiar with. It will state: “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.”

Why are they sending a test alert?

FEMA says the purpose of the Oct. 4 test is “to ensure that the systems continue to be effective means of warning the public about emergencies, particularly those on the national level.”

If the Oct. 4 test is postponed due to widespread severe weather or another significant event, a backup testing date is set for Oct. 11.