RC1001 Maritime Communication

You sit through your first class of the day just as your professor's handing out copies of a quiz—which, seeing as you didn't even know this class existed, you clearly haven't studied for. Seeing your expression of shock, he chuckles. "Just a quick review of our material; this one's about recognizing messages sent from foreign representatives." You look down at a particularly unintelligible diagram on the paper and gulp.