BACnet data communication protocol is ANSI / ASHREA standard, Latvian national standard ENV 1805-1, developed for building management systems.The aim of this standard is the opportunity to connect controllers of different manufacturers in one network and be able to manage systems from a single control computer.  BACnet - communication protocol designed specially for ventilation and air conditioning systems with the opportunity to connect to other types of systems such as: lighting, security, fire protection, heating and many others. BACnet is an American Standardization Institute ANSI standard, and there are exploring ways to incorporate it in International Standards Organization ISO standards.

BACnet protocol specifies a digital equipment data exchange and is based on four layers:

Each to BACnet standard appropriate equipment is defined by the BACnet standard relevant functional level, describing equipment, manufacturer, functions used BACnet objects.

BACnet protocol provides an opportunity to combine products from different manufacturers in a single network. The opportunity to operate in BACnet  scope, develops all powerful companies (Carrier, York, Siemens, Johnson Controls, Honeywell, Andover, Echelon, Delta Controls, Automated Logic, Krack, multistack; Air Monitor, Semco, METALAIR, Silicon Energy, Reliance Electric, Governair; Triatek, Dunham Bush, Vilter; Anemostat; Air-A-Plane, Weather-Rite; TSI; Cimetrics; Touch Plate; LightingInnovex; Lithonia; Simplex; NexLight, Phoenix Controls).