The Integrated Public Alert and Warning System on Wednesday will send a test message to everyone using a phone in the U.S. that runs on a network operated by a carrier participating in the the Wireless Emergency Alert system.
The objective of these tests, Johnson told CBS News, is to rapidly notify the country of a national crisis. The Communications Act of 1934 lets the president use private sector communication platforms for emergency messages.
With the IPAWS system, messages from local officials during an emergency will go out to the public on smart devices in a single alert. The message will be broadcast by cell towers for 30 minutes, so it's possible some people may get it at a different time. If a phone is off, or on a call at the time of the alert, the message many not come through.
The test is supposed to take place at 2:18 p.m. EDT on September 20.
"Presidential Alerts are to be used during a national emergency, though none have been sent to date", the agency said on its website.
If this had been an actual emergency alert, an official message would have followed the alert tone you heard at the start of this message.
Johnson directs the agency's public alert warning system that will send out the nationwide test of the presidential alert on Wednesday.
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There are three types of messages sent by WEA.
Because FEMA is a USA agency, the test will only take place in the U.S. Mistakes like that could make people nervous about this new nationwide alert.