US Patent 7752856 Monitoring and control system for air conditioner

An air conditioning monitoring and control system includes an air conditioner, a first air conditioning monitoring and control device and a second air conditioning monitoring and control device. The first air conditioning monitoring and control device communicates with the air conditioner via a first communication line. The first air conditioning monitoring and control device includes a first monitoring and control function and a second monitoring and control function. The second air conditioning monitoring and control device communicates with the air conditioner via a second communication line. The second air conditioning monitoring and control device includes the first monitoring and control function and a third monitoring and control function.