[EAS] Massage Length

[Sean Donelan]

On Fri, 31 Oct 2014, Richard Langevin - EMERMGTX wrote:
> I am updating our EAS messages for usage in an emergency and if I read all of the documentation correctly I have about 1750 characters and spaces for the message. I arrived at this from the CAP standard of 1800 characters minus the FCC required characters. So the question is, do I understanding this correctly?
>  From reading the message as it sits about 2650 characters and spaces it is right at 1:58 what am I missing?

My recollection was the 1800 character limit for CAP was primarily 
determined by various computer buffer sizes in character generators and 
other connected equipment. It wasn't directly tied to the EAS 2 minute 
limit.

At a standard radio announcer speed of 160 words per minute, 1800 
characters is slightly less than 2 minutes.  The Text-to-Speech settings 
in CAP-EAS boxes aren't specified, but most sound like they are in the 
range of 150 to 170 WPM.  If there is a problem downloading the CAP audio 
file, CAP-EAS boxes will fall back to Text-to-Speech, so speaking faster
on the recorded audio file may not help.

DHS and NIST have been funding some recent research on crisis and 
emergency communications on social media, including twitter, wireless 
emergency alerts, and the emergency alert system.  The research is
very, very early but the NIST technical report suggests keeping alert
text to less than 1380 characters, and speaking slightly faster than
a standard radio announcer at 175 WPM.  NIST also has some suggestions
for short message Twitter and WEA alerts.