alert - warning

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Common Alerting Protocol

The Common Alerting Protocol (CAP), a digital format for exchanging emergency alerts, allows a consistent alert message to be disseminated simultaneously over multiple communications pathways. FEMA has worked with the Organization for the Advancement of Structured Information Standards to develop the IPAWS standard.

 In addition to the basic CAP standard, a supplemental IPAWS Profile technical specification was developed to ensure compatibility with existing warning systems used in the United States. FEMA has formally adopted CAP and the IPAWS Profile to implement the Integrated Public Alert and Warning System (IPAWS).

Public safety organizations can use CAP to exchange incident reports and related information between different IPAWS-OPEN-compatible software systems.

CAP Implementation for IPAWS Fact Sheet

Benefits of Using Common Alerting Protocol

A single emergency alert can trigger a variety of public warning systems, increasing the likelihood that people receive the alert by one or more communication pathways. 

The Common Alerting Protocol can:

  • Add rich multimedia such as photographs, maps, streaming video and audio
  • Geographically target emergency alerts to a defined warning area. This is limited only by the capacity of the delivery system used.
  • Serve the needs of people who are deaf, hard of hearing, blind or low vision
  • Send alerts in multiple languages

EAS Participant Requirements

In 2012, the FCC required Emergency Alert System participants (radio, television, cable, satellite and wireline providers) to receive and distribute CAP-formatted alert messages from IPAWS.

As EAS rules and the CAP standards evolve, IPAWS-OPEN is updated to accommodate new requirements.

alert - info

For more information, send an email to the IPAWS Program Management Office at