Over 225 million of us just received a Presidential Alert test around 12:18pm mountain time. No, these aren't messages directly from President Trump's phone.

Here are the basics from FEMA regarding this Presidential Alert TEST:

WHY: The purpose of the test is to ensure that EAS and WEA are both effective means of warning the public about emergencies, particularly those on the national level. Periodic testing of public alert and warning systems helps to assess the operational readiness of alerting infrastructure and to identify any needed technological and administrative improvements.

HOW: 
The EAS and WEA test messages will be sent using FEMA’s Integrated Public Alert and Warning System (IPAWS), a centralized Internet-based system administered by FEMA that enables authorities to send authenticated emergency messages to the public through multiple communications networks.

WHO
: FEMA will administer the test, in cooperation with the FCC and the National Weather Service, and with the participation of the communications industry.

WHEN
: October 3, 2018, beginning at 12:18 p.m. mountain time on cell phones and 12:20 p.m. mountain time on TV and radio.