So I'm trying to reverse engineer something and came across something I've not seen, but I'm pretty much a beginner. A signal is fed into a tiny little circuit board composed of a regulated power supply and a single IC - a 7404 hex inverter. Tracing everything out, I found that what I have is an inputs that feeds into a not gate and the output from that feeds into the next not gate on the chip. It does this with two such signals. (The outputs go on to relays which ultimately turn on the coolant pump and the main motor on a CNC mill).
Until I saw this, I would have called a device that returns a 1 when given a 1 and a 0 for a 0 a wire. Is this just a matter of picking the right 7404 to turn a low quality signal into a nice clean signal, or is there something even more subtle that I'm missing?