A transport refrigeration system for a transportable temperature controlled space includes a compressor, a condenser and an evaporator fluidly connected to one another, an engine operatively connected to the compressor, and a fuel tank assembly fluidly connected to the engine. Each output beam of the OTDL is spatially distinguishable in free space. Prevailing conditions may also be determined and the transmission rate may be further adjusted based on the prevailing conditions. The sliding brackets are positioned and secured by means of a fastener to accommodate signs of different sizes. Communication is established from the user terminal using first events.