It will sound like an Amber Alert.
Mobile device users are going to probably be surprised when their phones go off on Wednesday.
About 225 million people across the U.S. will get an emergency alert starting at 11:18 PST on October 3.
This will be the first-ever cell phone emergency alert.
The alarm will resemble that of an Amber Alert said the Federal Emergency Management Agency.
The subject will read: "Presidential Alert," according to the Associated Press: "THIS IS A TEST of the National Wireless Emergency Alert System. No action is needed."
Soon after the above alert a test of the broadcast system will take place.
Although the majority of people will get the initial alert, some will get it at different times.
This alarm would be used to signal citizens of a national emergency.