ACU230 is designed for cell site or power site to keep suitable & accurate room temperature for devices. ACU230 can automatically control & transfer one or two air conditioners by following user's settings & sensing by an up-to 10 meter long digital temperature sender cable. When temperature is lower than user's setting, ACU230 shuts down both air conditioners to save power. Under normal temperature condition, ACU230 can automatically transfer air conditioners by user's time setting in order to extend air conditioner's service life. ACU230 also monitors AC input power status to protect air conditioners from abnormal power source.