An air conditioner type called a split air conditioner has its compressor, expansion valves, and cooling coils outside the wall. It also goes by the name outside condenser units or outdoor units. A single outdoor unit communicates with several inside devices that may all be commanded by a single remote. The outdoor unit is linked to the indoor units through copper pipes that connect to the internal evaporator coils or rubberized hoses. The inside air must be cooled and made more humid, and that job falls to the outdoor crew.