BACnet® (Building Automation and Control Network) is the ASHRAE (American Society of Heating, Refrigeration and Air-Conditioning Engineers) building automation and control networking protocol. It is a non-proprietary (open) protocol that defines how a control system communicates with end-devices (objects) is a building automation network.
BACnet® was designed to meet the communication needs of building automation and control systems for applications such as heating, ventilating, and air-conditioning control; video security systems; energy management; lighting control; and physical access control.
The BACnet® protocol provides mechanisms for computerized building automation devices to exchange information, regardless of the particular service they perform within a facility. It is such a prominent building automation protocol that it has been adopted as both an ANSI and ISO standard.