This box can be placed next to a Signal Receiver Box and will then send the Signal Aspect from the Receiver Box to a paired Receiver. Multiple Controller Boxes can be placed next to a single Receiver Box. This enables a single Block Signal to control multiple Switch Motors or Distant Signals.
Placing two Receiver Boxes next to a Controller Box will cause the Controller Box to send the most restrictive Signal Aspect between the two. Additionally it can be powered via Redstone to emit an Aspect chosen via a GUI.
It will not activate on the Redstone current emitted directly from a Signal Receiver Box. It will however always emit the most restrictive Aspect between the one chosen in the GUI and one received from a Receiver Box. You cannot link a controller to two receivers. Placing a receiver next to a controller will make the receiver give information to the controller but will not actually link them together.