The Black Box works and shows some devices however, I have the 999si HD and tried to get it to work with my EV-200.  Basically I needed the GPS from my Humminbird to use on my EV-200 for plotting - does not work and cannot get humminbird to answer why not.  I plugged in a Ray Marine unit and everything worked so its not the network.   Terrible Humminbird service response and looks like I will be moving over to Ray Marine totally.   I guess if you didn't buy the AutoPilot from Humminbird they have selective help for you.