Are you ready for an emergency? Whether or not you are, FEMA in partnership with the Federal Communications Commission and the U.S. broadcast and cable industry is testing their Emergency Alert system on Wednesday to make sure emergency messages can be broadcast nationally.

The test will begin at the same time across the country: 2:20pm ET, 1:20pm CT, 12:20pm MT, 11:20am PT, 10:20am AT, and 8:20am HT.

The National Periodic Test message will be broadcast to all U.S. AM, FM, TV, cable and direct satellite broadcast stations. Unlike previous tests, the emergency message will not trigger alerts on cell phones and will not rely on internet technology for rebroadcast. FEMA says they want to gauge the preparedness of the alerting system when there’s no internet access, which they say is important if a crisis knocks out data but not power.

As has been the case in previous nationwide tests, the alert will look and sound just like required monthly tests required of EAS participants.

According to FEMA, the test is a key way to assess the operational readiness of the nation’s alert and warning infrastructures for distribution of a national message, as well as to determine if technological improvements are warranted.

In the event that the test is postponed due to some pressing major event, such as a major natural disaster, officials will postpone it.

Federal law requires FEMA to conduct a nationwide EAS test at least once every three years. “Routine tests help ensure the alert system is ready to provide timely information when it matters most,” said FEMA, adding, “Following the test, FEMA and our partners will review the results and identify opportunities to strengthen future alerting capabilities.”