What do you mean by Audible Scilence? Because the Way System Sensor sync works is by controlling how much time the NAC is on and Off (Sync Signal). An older post shows these timings in more detail, but Ill sum it up here.
I Implemented these timings into my Universal Strobe Sync Protocol, and it works with my System Sensor and some of my Gentex Equipment.
I would look into that post for more detail and for the Audible Scilence timings.