If I use a tractor to tow a trailer, how do my trailer brakes work?

If I use a tractor to tow a trailer, how do my trailer brakes work?

If it is light mounted, it can be directly connected with the tractor and rely on the all wheel braking system of the tractor itself. If it is heavily mounted, our tractor enables to be equipped with a pneumatic system, which could be connected with the trailer's braking system to provide power.