[EAS] Tsunami Warning - No Audio

[Harold Price]

There has been some discussion of what the Sage ENDEC does with the 
attention tones at the start of EAS or NWS/SAME messages. For 
completeness, here is a detailed description.

The ENDEC looks for the presence of those tones only to remove 
them.  The sequence is:

Hear a 2nd matching eas header, start the recorder.
Hear a 3rd header, restart the recorder.
If a two-tone or 1050hz tone is detected within a dwell time, wait 
until it goes away, then restart the recorder.
Hear the end of message data, stop the recorder.

This means that if the audio quality is not sufficient to detect the 
tone, it will simply appear in the replayed audio, but the audio 
should still be present.  The ENDEC waits for the start of the two 
tone for a few seconds (the EAS spec says it should start one second 
after the last header) and will ignore it after that.  It waits 
longer for the start of the 1050 hz tone before ignoring it. In the 
old days, that tone sometimes took several seconds to start.  The NWS 
upgraded their system once or twice since 1997, and the tone appears 
more quickly now.

That is what is supposed to happen.  If your ENDEC is not working 
this way, send me an email.

Harold