[Milsurplus] BROFICON?

[David Stinson]

Immediately after 9-11, a couple of the AM broadcast stations 
here in Dallas began sending a short AFSK data burst 
at a low modulation level at the top of
the hour and at the half hour.  Kept it up for some time.
I don't know what it was, but
I would think it was intended as some sort of emergency comm.
KLIF 570 (or maybe it's WBAP- don't remember right now)
still has these low-level data bursts from time to time, but seem
to be in a different format; perhaps these are for their remotes or
something.  One of  you broadcast engineers know about this?
D.S.