alert - warning

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Emergency Alert System Participants

Emergency Alert System (EAS) participants are our nation’s radio and TV broadcasters, cable TV, wireless cable systems, satellite and wireline operators. They are the stewards of EAS in close partnership with alerting officials at all levels of government. Alerting authorities use the system to disseminate detailed public safety messages by broadcast, cable, and satellite channels.

In January 2012, the FCC announced its Fifth Report and Order to clarify FCC rules relating to CAP implementation. Among the provisions is a new requirement for EAS participants’ EAS equipment to interface with Integrated Public Alert and Warning System to enable the distribution of CAP-formatted alert messages from the IPAWS system

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.  

Broadcasters participate in EAS is by using the EAS CAP Feed.

How Does It Work?

1. Authorized public officials send emergency messages using CAP.

2.The IPAWS Open Platform for Emergency Networks (IPAWS-OPEN) collects the CAP emergency messages and distributes them to EAS participants through an EAS CAP Feed.

3. To connect to the feed, EAS participants require an internet connection to poll IPAWS-OPEN, or other CAP based networks, and CAP based equipment, known as encoders/decoders.. As required by the FCC and state and local EAS plans, EAS devices at radio and television stations also monitor other stations for EAS alerts in a "daisy chain" independent of the internet.

Common Alerting Protocol Version 1.2

CAP is an international standard developed by FEMA and the Organization for the Advancement of Structured Information Standards (OASIS).

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FEMA adopted Common Alerting Protocol Version 1.2 in 2010. An OASIS Technical Committee Specification further enhanced the CAP Version 1.2. IPAWS ensures that CAP data is compatible with U.S. alert distribution pathways, including the EAS.

CAP-based networks do not replace:

  • Resiliency of over-the-air methods of monitoring EAS tones
  • EAS protocol, which is compatible with the National Weather Service’s Weather Radio Specific Area Message Encoding (SAME)

Encoder/Decoder CAP Conformity

The IPAWS Guide for Independent Testing of Emergency Alert System Equipment provides information about FCC equipment certification requirements. The guide can be used by independent testing authorities that provide testing services for EAS decoder equipment manufacturers.

CAP-based equipment does:

  • Translate CAP messages to the EAS protocol and message format
  • Consist of stand-alone converters, firmware upgrades to existing encoders/decoders, or newer encoder/decoder models where CAP is integrated
  • Convert CAP to EAS/SAME protocol using EAS CAP Industry Group recommendations

Monitoring IPAWS-OPEN

CAP-compatible EAS equipment can poll the IPAWS-OPEN system. Once equipment manufacturers update and release their firmware for this new system, EAS participants can enter into encoder/decoder devices.

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Note: CAP-compatible EAS equipment manufacturers must provide firmware updates. EAS participants should check their equipment manufacturer’s website for information on when these software updates will be available.

Testing with IPAWS-OPEN

In each of the nine U.S. time zones, every Monday at 11 a.m. local time, FEMA generates a Required Weekly Test message that is transmitted to all 50 states. States with two time zones are assigned to the time zone that includes the largest area within the state. These log-only, non-disruptive internal test messages allow EAS participants to verify their configuration and message connections.

Learn More

View an IPAWS Architecture Diagram for a flowchart of how alert authorities send messages through the IPAWS-OPEN aggregator.

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For more information, send an email to the IPAWS office.