It doesn't react at all to any signals from Rivet. I haven't tested whether it reacts to a stop signal. The only thing that ZUB did was overspeed protection (at 15 over speed limit it warns you, at 20 over limit it applied the brakes)
With the ones from Schuster, it does receive signal information. But it doesn't work properly.
For example, I passed a signal with 60 now and 40 at the next signal. It showed 90 at the display and the red light on the ZUB display was lit. Which isn't supposed to happen.
Another signal was full clear. I was accelerating to 90 kph (which was the allowed line speed), about 10 metres before passing it, I received a Zwangsbremsung out of nowhere while at approx. 80 kph.
I haven't seen any ZUB working properly. Not Rivet's, not RWA's and not K-Trains's