Check on various brake systems some use a "box" some use a cilinder that goes under the dash and you do not see it and others use different methods to accomlish the task, some use radios to control the "box" and some boxes are self cotained and have diffrent adjustment methods.
The SMI that I have is a "box" type and hooks to the vacum hose of the booster via a "T" fitting in the hose from the engine to the booster and into the cabin, it also attaches with a piston from the box to the brake pedal, and has a connector for the electrical signals from the cab controller via a 4 wire cable to the rear of the motor home.
Then a connecting cable between the motor home and the fornt of the toad to the box toad, in the toad I have a wire from the battery to the box with a fuse in line that not only provides power but also works with the emergency brake feature of the box.
I also have a 7 pin cable with connectors that carry the turn signals, stop signal, clarance lights and negative and positive power so that when the toad is hooked to the RV the battery in the toad is being charged.
I have a cable from the control box in the cabin in the "C" cabin and all the way the toad, I personally do not like radio contrled units, but thats me.
I hoppe that you can use the above, as I said before look into all systems and choose the one that you will be more comfortablle with.
navegator