The alert system was initially designed in the 1950s, but it has never gone through an end-to-end, nationwide test. Officials want to know the system will work should they need to alert a large region of the US to an emergency. They stress the 30-second drill is not the real thing.
On Wednesday afternoon, while you are watching television or listening to the radio, expect that program to be briefly interrupted. The test is a coordinated effort by the Federal Emergency Management Agency and the Federal Communications Commission to assess the reliability and effectiveness of the alert.
"Once we test the system, we'll identify those areas that we need to improve upon with the goal of actually modernizing the system," said Andrew Velasquez, FEMA regional director.
Velasquez says that while Wednesday's emergency alert system test will resemble the periodic, monthly tests most of the public knows, the fact that all radio, broadcast and cable stations across the country will carry the test at the same time might alarm some viewers.
"Regardless of what they will see, we want folks to know that it's just a test," Velasquez.
There will be some differences in what viewers see. If you receive TV with an antenna, a graphic will be shown for the duration of the test for people watching ABC7 over the air. But because of limitations in the old alert system, not all cable systems may be able to carry the words "this is a test" on some TV screens, even though the accompanying audio message will state "this is a test." That's why the Office of Emergency Management and Communications is prepared for an uptick in 911 calls from concerned viewers.
"We're geared up here for the 911 calls to let people know that we're not in some sort of dire emergency," said Gary Schenkel, executive director, OEMC.
Once the test is over, the program you were watching should return, but not everyone will be flipped back. If that happens, experts recommend that you unplug your cable box. The FCC will be monitoring the results of the test.