Federal Commercial Mobile Alert System (CMAS)


Have you ever thought that, for emergency alerts to be distributed as quickly as possible, they should be sent to cell phones? The Federal Communications Commission (FCC), along with the Federal Emergency Management Agency (FEMA) and the wireless industry, are working to make that possible.

What is the Commercial Mobile Alert System (CMAS)?

CMAS (also known as Wireless Emergency Alerts (WEA) or Personal Localized Alerting Network (PLAN)) is a new public safety system that allows customers who own an enabled mobile device to receive geographically-targeted, text-like messages alerting them of imminent threats to safety in their area. The new technology ensures that emergency alerts will not get stuck in highly congested user areas, which can happen with standard mobile voice and texting services. CMAS was established pursuant to the Warning, Alert and Response Network (WARN) Act.

CMAS enables government officials to target emergency alerts to specific geographic areas through cell towers (e.g. lower Manhattan), which pushes the information to dedicated receivers in CMAS-enabled mobile devices.

CMAS complements the existing Emergency Alert System (EAS) which is implemented by the FCC and FEMA at the federal level through broadcasters and other media service providers.

Wireless companies volunteer to participate in CMAS. CMAS is the result of a unique public/private partnership between the FCC, FEMA and the wireless industry with the singular objective of enhanced public safety.

Participating wireless carriers were required to deploy CMAS by April 7, 2012.

How does CMAS Work?

Authorized national, state or local government officials send alerts regarding public safety emergencies, such as a tornado or a terrorist threat to CMAS.

CMAS authenticates the alert, verifies that the sender is authorized and sends it to participating wireless carriers.

Participating wireless carriers push the alerts from cell towers to mobile devices in the affected area. The alerts appear like text messages on mobile devices.

Who will receive CMAS alerts?

Alerts are geographically targeted, so a customer living in New York would not receive a threat if they happen to be in Chicago when the alert is sent. Similarly, someone visiting New York from Chicago on that same day would receive the alert. This requires a CMAS enabled mobile device and participation by the wireless provider in CMAS.

How much will consumers pay to receive CMAS alerts?

Alerts are free. Customers do not pay to receive CMAS alerts.

Do consumers have to sign up to receive alerts?

Customers of participating carriers are automatically signed up. CMAS allows government officials to send emergency alerts to all subscribers with CMAS-capable devices if their wireless carrier participates in the program. Consumers do not need to sign up for this service.

What alerts will CMAS deliver?

Alerts from CMAS cover only critical emergency alerts. Consumers will receive only three types of alerts:

  1. Alerts issued by the President
  2. Alerts involving imminent threats to safety or life
  3. Amber Alerts

Participating carriers may allow subscribers to block all but Presidential alerts.

What will consumers experience when they receive a CMAS alert?

A CMAS alert will be accompanied by a unique attention signal and vibration, which is particularly helpful to people with hearing or vision-related disabilities.

Will consumers be able to receive CMAS alerts on a prepaid phone?

Yes. Consumers with prepaid phones can receive CMAS alerts as long as their provider has decided to participate in CMAS and the customer has a CMAS-enabled device. Such consumers will receive CMAS alerts just as customers with postpaid, monthly service will.

Will CMAS track my location?

No. CMAS is not designed to – and does not – track the location of anyone receiving a CMAS alert.

Are CMAS alerts text messages?

No. CMAS alerts are transmitted using a new technology that is separate and different from voice calls and SMS text messages. This new technology ensures that emergency alerts will not get stuck in highly congested user areas, which can happen with standard mobile voice and texting services.

Will consumers need a new phone or a smart phone to receive alerts?

Some phones may require only software upgrades to receive alerts, while in other cases a subscriber may need to purchase a new CMAS-capable device. Consumers should check with their wireless carrier regarding the availability of CMAS-capable handsets.

Will CMAS be available everywhere?

Participation in CMAS by wireless carriers is voluntary. Some carriers will offer CMAS over all or parts of their service areas or over all or only some of their wireless devices. Other carriers may not offer CMAS at all. Consumers should check with their wireless carriers to determine the extent to which they are offering CMAS.

Can consumers block CMAS alerts?

Partially. Participating wireless carriers may offer subscribers with CMAS-capable handsets the ability to block alerts involving imminent threats to safety of life and/or AMBER Alerts; however, consumers cannot block emergency alerts issued by the President.

Why can't consumers block CMAS alerts issued by the President?

In passing the WARN Act, Congress allowed participating carriers to offer subscribers the capability to block all CMAS alerts except those issued by the President.

How will subscribers know if their carrier offers CMAS?

The FCC requires all wireless carriers that do not participate in CMAS to notify customers. Consumers should check with their wireless carriers to determine the extent to which they are offering CMAS.

My friends and I have the same wireless carrier. They just received a CMAS alert over their cell phones, but I have not. Why?

Some participating carriers are offering CMAS on some, but not all, of their mobile devices. Consumers should check with their wireless carriers to find out if their cell phone in CMAS-capable.

Information about CMAS-capable handsets can also be found at CTIA.org.

Why are some consumers receiving CMAS test alerts on their mobile phones?

Participating wireless carriers are required under FCC rules to conduct periodic testing of their CMAS infrastructure. As part of their test, some participating carriers may choose (but are not required) to send test alerts to CMAS-enabled handsets. Consumers with questions about these test messages should contact their wireless carriers.

For More Information

For information about other telecommunications issues, visit the FCC's Consumer and Governmental Affairs Bureau website, or contact the FCC's Consumer Center by calling 1-888-CALL-FCC (1-888-225-5322) voice or 1-888-TELL-FCC (1-888-835-5322) TTY; faxing 1-866-418-0232; or writing to:

Federal Communications Commission
Consumer and Governmental Affairs Bureau
Consumer Inquiries and Complaints Division
445 12th Street, SW
Washington, DC 20554.

This information has been provided by the U.S. Federal Communications Commission (FCC) CMAS website.