Maybe it's just me, but there are three things about this circuit found in the EPIC operation guide that strike me as overlooked/sloppy...
First of all, that's an LED in the middle. It took me a little while to figure out that it's not just a seemingly randomly placed diode with arrows coming out of it. Correct me if I'm wrong, but I conversed with a friend of mine about it and that's what he got out of it too.
Second, it's supposedly a Schmitt trigger. Again correct me if I'm wrong...but this is just a decoupled 3.3v.
Third, it's going out to a LEMO connector, not a BNC, correct?
I could be totally wrong about everything here, but this is just what I got out of it.