A nationwide test of the emergency and wireless alert systems will be conducted Wednesday at 2:20 p.m. ET, when a message will be sent to all cellphones, TVs and radios.
The Federal Emergency Management Agency said in a news release in August that a message that reads, “THIS IS A TEST of the National Wireless Emergency Alert System. No action is needed,” will be sent to all phones. A Spanish version of the message will be displayed depending on the language settings of the devices.
A separate message will be sent to radios and televisions, saying, "This is a nationwide test of the Emergency Alert System, issued by the Federal Emergency Management Agency, covering the United States from 14:20 to 14:50 hours ET. This is only a test. No action is required by the public."
The test is a joint operation between FEMA and the Federal Communications Commission, meant to “ensure that the systems continue to be effective means of warning the public about emergencies, particularly those on the national level,” according to the August news release.
If it's being sent over the cell phone carrier signal, does that mean if you're at home, or otherwise connected to Wi-Fi, that you won't get it?
No, even on WiFi your phone maintains its cellular signal, even data depending on your settings (it's just not actively used as wifi will be considered superior).