3.3 what is wabco’s iabs trailer abs? Web the system processes data for more than 40 supporting functions to ensure shorter braking distances and control air suspension levels. Web after completing the training, the participant can describe the structure and the mode of operation of compressed air brake systems in trucks, buses and trailers. 2s/1m (basic and standard), 2s/2m, 4s/2m and 4s/3m systems. If you are mounting on a bracket, connect the air supply line from.