We interrupt this story for an important announcement: Today the Department of Homeland Security and the Federal Communications Commission will hold the first nationwide test of the Emergency Alert System.

The test will occur at 2 p.m. ET and will be carried on all broadcast television, radio stations and cable and satellite television systems in the U.S. and U.S. territories.

The Federal Emergency Management Agency has more information and videos  here.

The national public warning system has been used by state and local authorities for tests and notifications such as Amber Alerts and weather warnings but there has never been a nationwide test.

The Emergency Alert System was designed in the 1950s and is run by the Federal Emergency Management Administration and the FCC. President Bush signed an executive order in 2006 to mandate the nationwide system and national alert capability.

Because the national system has never been tested, homeland security officials say this is an important trial to see how it works. It is expected to last 30 seconds.

FEMA and the FCC want to ensure that the deaf and those hard of hearing, people with cognitive or mental health concerns, senior citizens, and people not proficient in English are aware of it.

“You may not see the familiar test banner crawling across your screens. We want you to know this is a test,” FEMA administrator Craig Fugate said in a recent video posted on FEMA’s website.

“It’s our opportunity to check to make sure that our systems are working across the country if we have a national emergency.  Because of the system design not all of you will see the crawl that says this is a test.  It will say this is an emergency alert. But we want you to understand this is a test,” Fugate said.

Officials say the system could be used to ensure that the president and officials can address the nation during a significant emergency such as a natural disaster, terrorist attack or cyberincident.

DHS and FEMA are currently working on expanding the Emergency Alert System by developing the Integrated Public Alert and Warning System, which will allow nationwide alerts to be sent to wireless mobile devices and phones.

Working with the FCC, the two agencies are also working on the Commercial Mobile Alert System and the Personalized Local Alert Network, which would allow local alerts to be sent via wireless technology and devices.