Alaskans tuning in to their radios and TVs Wednesday morning will witness the first national emergency exercise of its kind.

Radio, television and cable providers are participating with federal and Alaska partners in a live statewide test of the nation's Emergency Alert System that's employing a never-used code to be applied in a national crisis. The test, set to begin at 10 a.m. (AST), will help officials prepare for a future national exercise not yet scheduled, according to the state and federal officials.

The three-minute airing, to be activated by the Federal Emergency Management Agency, is unlike regular periodic tests aired by broadcasters. It's the first official activation of the Emergency Action Notification code, which technically gives the president access to airwaves to address Americans during a national crisis.

"This exercise, using a live code, will broadcast a test message across the State of Alaska and provide us with valuable information on the readiness of the EAS to handle a presidential message in an actual emergency," FEMA spokesman Clark Stevens said in an e-mail.

Participants, which include the Federal Communications Commission, said the exercise has been in the planning since September. The Alaska Broadcasters Association developed public service announcements on the exercise that began airing Dec. 21, said the association's executive director, Darlene Simono.

Alaska was chosen for the initial test run for several reasons, said Bryan Fisher, chief of operations at the Alaska Division of Homeland Security and Emergency Management. Alaska is well-versed in similar exercises conducted through the national public warning system to test tsunami warnings and Amber Alerts within the largest state in the country. Parts of the system also are commonly used by states for severe weather alerts.

"We pretty much have the technology," Fisher said. "If we can prove the system works with the geographical and technical challenges in Alaska, it should work anywhere."

Alaska's extreme isolation also cuts down on the chance of the test reaching beyond state lines and mimicking a glitch that originated in the Chicago area a few years ago, Fisher said.

In June 2007, tones from the Emergency Alert System were inadvertently broadcast on Illinois radio and TV stations, sporadically interrupting programming. FEMA said at the time that other states tied to the Illinois broadcast network were potentially affected.

The agency said it was installing a new satellite warning system and that the tones were part of a test that were intended to be heard internally but were accidentally broadcast instead. FEMA blamed a contractor's installation error.