EAS, IPAWS evolve to meet government mandates

Starting in 1951 with the Control of Electromagnetic Radiation (CONELRAD), which evolved into the Emergency Broadcasting System (EBS) and finally the Emergency Alert System (EAS), the U.S. government has made it a point to have some sort of emergency alert system to inform the public of a large-scale national disaster. Using the public airways was a logical choice to alert a large and diverse population. Later it was refined to enable smaller areas to be alerted to local emergencies such as storms or gas leaks.

The technology itself has evolved from a two-tone alert signal to what some describe as the “duck quack” of the present EAS that sends text information via an acoustic modem over the air waves. But the next evolution of EAS has begun, and its next phase will start this year. This transition will require several changes at the station level as well as changes to the rules that govern EAS.


The Integrated Public Alert and Warning System (IPAWS) is the newest incarnation of the U.S. national alert system. It was developed back in 2006 to allow the president to be able to address the country within 10 minutes of a national emergency and is administered by the Federal Emergency Management Agency (FEMA), which operates under the Department of Homeland Security. Integrated is the key word, because this system attempts to consolidate all emergency alerts into a single notification system with a common message format.

IPAWS’ top priority is to be able to get a national alert message out to the public as quickly as possible. To do this, the system has adopted a message format used for all alerts and messages, called Common Alerting Protocol (CAP). To enable that message to get to the public, operators are using all available means of communication, including cell phones, Internet messaging, pagers, road signs, landlines, satellites and, of course, TV and radio.


CAP is a text-based message format that uses XML, much like HTML used in Web pages where tags are used to surround and label information.

The FCC currently is waiting for FEMA to approve Version 1.2 of CAP, which should take place later this year. Once it is approved, the FCC will rewrite its EAS rules to include CAP and IPAWS as a source for EAS messages. (See Figure 1.)

CAP will allow all the different types of communication channels to be able to carry its messages in a human- and machine-readable format. It also allows for a wider range of messages and is open to future development and extension.

EAS as part of IPAWS

EAS used to be the tool to alert the public, but it’s now just part of a larger system of communication channels. And to be part of this system, EAS needs to be able to handle the type of messages being used with IPAWS, which means understanding CAP messages.

All EAS equipment manufacturers have developed adapters or new equipment that can handle CAP messages and the method in which they will arrive. EAS used radio receivers to listen for alerts from the LP and NOAA stations, but with IPAWS, the EAS decoders will also have to monitor the Internet.

Soon every radio and TV station will need an Internet connection to be able to receive CAP messages from IPAWS. The adapters from EAS manufacturers will convert the CAP message into an audio signal that the EAS decoder can understand, which will enable a normal EAS message to be sent over the air.

These adapters are actually dedicated computers with Ethernet, USB ports and internal hard disks. The good thing is that with the computer also comes a monitor and keyboard, making setup much easier than it was with those little two-line LCD displays on the front of EAS equipment.

How EAS works with IPAWS

Similar to current practices, going forward, all stations will need to monitor at least two LP stations in their area. In each state, there are two national Primary Entry Point (PEP) radio stations. These stations are equipped with generators as well as landlines, satellite reception and high-frequency radios that allow them to receive messages directly from FEMA. As these stations transmit an EAS alert, it daisy chains from station to station around the state. National Public Radio’s satellite, as well as XM satellites, are now being used by FEMA for EAS messages to the PEP stations.

Once CAP 1.2 is implemented and equipment is installed, each station will be monitoring the Internet for IPAWS messages. These messages will originate from one or more sources: federal, state, local government or first responders. Stations can then tie into the IPAWS IP and satellite networks to disseminate an alert message to all monitoring points.

These distribution points, such as Internet, landline services, radio and TV stations, mobile service providers and commercial satellite uplink facilities, will have the responsibly to authenticate the IPAWS message using their CAPS equipment before forwarding the message. Authentication includes making sure the alert pertains to that provider’s service area.

In the case of EAS, this means that the CAP adapter will decode the message and feed it to the EAS equipment for broadcast; as with messages received from radio stations, the EAS decoder will only output one EAS alert even if multiple of the same alert are received.

What the public will see

During an alert, the public will see the normal EAS messages from their local TV and radio stations as well as from their cable TV provider. But now they will now receive alerts from several new places (See Figure 2.):

  • RSS feeds
  • Computers and mobile devices
  • Cell phones
  • Landline telephone voice calls
  • NOAA radio
  • RBDS (Radio Broadcast Data Systems) from FM stations
  • Web pop-ups
  • SMS texting
  • Satellite radio
  • Satellite TV
  • DHNS (Deaf and Hard-of-Hearing Notification System) through online videos
  • Road signs
  • Public area signage


The clock will start ticking once FEMA approves CAP 1.2 later this year. Once that happens, the FCC will quickly update the Part 11 rules covering EAS to incorporate the CAP message and delivery formats. Then the race will be on for manufacturers to prepare any and all equipment they have designed to handle CAP. From there, it’s up to the broadcasters to purchase this equipment and set it all up.

What you can do

The first thing broadcasters should do is find out if their present EAS equipment can be upgraded to handle the new CAP requirement or purchase a new system, if necessary; fortunately, most manufacturers have developed adapters to do just that. The next step would be to install a dedicated, reliable Internet connection for the new CAP equipment.

As always, EAS systems should be tested on a regular basis by broadcasting weekly tests and monitoring and forwarding the monthly tests. But because the FCC has not rewritten the EAS rules, no one knows what type of tests will be required for the new CAP/IPAWS system.