8
Sage Digital ENDEC Manual Rev 2.0
7.1 Over the Air
Your ENDEC receives alerts via the analog audio inputs on the back of the unit. Your state’s EAS plan
will define what your monitor assignments are. The audio relay of alerts is an important backup capability
to CAP delivered messages, and is a critical part of FEMA’s mandate to provide the President with
communications capability to address the American people within 10 minutes during a national emergency
Some messages are not originated as CAP messages and always only use the audio relay method of
dissemination.
7.2 Common Alerting Protocol
The Common Alerting Protocol (CAP) is an international standard for sending alert information. The CAP
allows a consistent alert message to be disseminated simultaneously over many different communications
systems. A CAP message is not sent on the main audio output of a broadcaster like an EAS alert. CAP
delivery varies from state to state, but typically includes one or more of:
• over the Internet from FEMA’s IPAWS system,
• over the Internet from a state or local alert originator via a 3
rd
party alert aggregator,
• via an IP data stream from satellite.
In any case, the last hop is via the LAN connector on the ENDEC.
It is important to note, however, that a CAP message is always converted to an EAS message before it is
broadcast by an EAS participant.
There are a few major differences between a CAP message and an EAS message:
• CAP contains free-form text. For example, rather than a simple “Child Abduction Warning issued
for Allegheny County”, the alert contains specific information. If a missing child, the text could
include a description of the child, last known location, what type of car is involved, and other
important information. This information is available to any of the text outputs of the ENDEC,
such as printer, email, LED sign, video crawl, HD radio, etc. The additional text information is lost
when the alert is turned into EAS for relay, but stations that receive the CAP message can make use
of the text.
• CAP contains digital audio. This is usually in the form of a pointer to an audio file on a web
server. The ENDEC can then fetch the audio and use it when sending the alert. In most cases, the
quality of audio in the digital file will be better than the quality of audio that is received from an
over-the-air source and relayed.
• In some cases, if the CAP alert does not contain audio from the originator, the ENDEC can provide
audio by converting the CAP text to speech.
As with EAS messages, the ENDEC uses the filter information you provide to decide what types of CAP
alerts to put on the air. The ENDEC automatically converts a CAP message into an EAS message for
broadcast.
To read more about CAP, see also:
• the Sage web site (www.sagealertingsystems.com
)
• the FEMA web site: https://www.fema.gov/common-alerting-protocol.
To Next Page
Loading...