🚀 go-pugleaf

All this talk of VCR commercial eliminators brought to mind something
I ran into a couple of years ago (circa 84 or 85, maybe) while chief
engineer at an ABC station.  If I recall correctly, there was a
code of some sort which network included in the vertical interval
of shows coming down the line (it really was a "line" then :-) )
to us.  Supposedly, we were required to pass it unmolested through
the transmitter and onto the air.  Somewhere in our viewing area, 
there was a receiver/decoder/etc. system which would monitor this
code.  The whole idea was to make sure we were not clipping network
programming by sneaking in additional commercials in the avails.
slot, or rolling our own spots over network ads (except in the case
of scheduled cut-ins, whereupon they probably checked to see if we
missed it or not).  Seems like it went by the name "AMOL" --- for
Automated Measurement of Lineup, or something to that effect.  Maybe
it even had to do with automating the Nielsen diary process, or
something like that?  
In any case, I can't believe that I'm imagining this but don't recall
any details or hearing any more about it.  It would make for a
dandy commercial eliminator if you knew how it was sent, and if it
indeed is still there.
Maybe a check of old issues of "Broadcasting" would turn something
else, or a friendly query to your local chief engineer type.