The American federal government is conducting a nationwide test of its Emergency Alert System that will alert all consumer cell phones. Here's what you need to know.

The Federal Emergency Management Agency (FEMA) and the Federal Communications Commission (FCC) will conduct an emergency alert to all consumer cell phones on Wednesday, October 4, at 2:20 p.m. ET. This test measures the effectiveness of Wireless Emergency Alerts to determine how well FEMA can alert people of emergencies via cell phone.