If your phone starts going crazy this week, don’t be alarmed – it’s only a test.

FEMA will be launching a Nationwide Emergency Alert Test this Wednesday. Every cell phone, radio, and TV will blare that familiar warning tone, followed by a voice explaining it’s only a test.

“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. In case the Oct. 4 test is postponed due to widespread severe weather or other significant events, the back-up testing date is Oct. 11, ” the Federal Emergency Management Agency, which is conducting the test in coordination with the Federal Communication Commission, said in a statement.

The test is scheduled for Wednesday, Oct. 4th at 2:20pm ET. It will last roughly one minute.

FEMA said the message 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.”