Don’t let today’s test of the emergency alert system catch you by surprise.

The nationwide test will include the Wireless Emergency Alert and Emergency Alert System today (Wednesday, Oct. 4) starting at 2:20 p.m. ET (1:20 p.m. CT).

The WEA portion will include messages sent to cell phones. Displayed in either Spanish or English depending on the phone’s main menu settings, the English message will say “THIS IS A TEST of the National Wireless Emergency Alert System. No action is needed.”

Phones set in Spanish will display “ESTA ES UNA PRUEBA del Sistema Nacional de Alerta de Emergencia. No se necesita acción.”

All cell phones within the range of active towers with a wireless provider that participates in WEA should be capable of receiving the message. Messages for phones used by people with disabilities include a unique tone and vibration.

Alert tones are generally only played with the text is initially received by the phone, FEMA said, and, on most devices, stop as soon as the user clicks a butter. If the phone is off before the test alert is sent and not turned back on in the 30 minutes in which the test is being conducted, it will likely not get the text message.

In a non-test situation, WEA alerts are used to send national emergency notifications from the president or FEMA, AMBER alerts about missing children and public safety messages about imminent threats or other safety recommendations.

The EAS portion of the test will be sent to radios and televisions. The EAS test will last one minute and will include broadcasts on radios and televisions, cable systems and satellite radio.

Test messages will be similar to the regular monthly EAS broadcasts and will say: “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.”

In the event of widespread severe weather or other significant event, the tests will be delayed until Oct. 11, FEMA said.