Don’t panic – this is only a test.

The Federal Emergency Management Agency and the Federal Communications Commission will conduct the first-ever nationwide test of the Emergency Alert System today at 2 p.m. ET.

That means if you are watching television or listening to the radio at that time, you will see or hear the test broadcast, which may last up to three and a half minutes.

Though similar tests are regularly conducted at the local and state level, this is the first time the system has been tested nationally, the agencies said in a statement. The system would allow the president to address the American people during a national emergency.

“Because there has never been an activation of the Emergency Alert System on a national level, FEMA views this test as an excellent opportunity to assess the readiness and effectiveness of the current system,” said Damon Penn, FEMA’s assistant administrator of national continuity programs. “It is important to remember that this is not a pass or fail test, but a chance to establish a baseline for making incremental improvements to the Emergency Alert System with ongoing and future testing.”

Here are the key things you need to know about the test:

• It will be conducted Wednesday, Nov. 9, at 2 p.m. ET.
• It will be transmitted via television and radio stations within the United States, including Alaska, Hawaii, the territories of Puerto Rico, the U.S. Virgin Islands, and American Samoa.
• Similar to local emergency alert system tests, an audio message will interrupt television and radio programming indicating: “This is a test.”
• When the test is over, regular programming will resume.