BACnet

BACnet (Building Automation and Control network) is ASHRAE's open standard for building management systems (BMS): HVAC, lighting, access control and metering. It defines standardized objects and services that let equipment from different vendors talk to each other.

It travels over MS/TP (RS-485) in the field and over BACnet/IP at the network level, and commonly coexists with ModbusMProtocolModbusThe most widespread industrial fieldbusView profile and KNXKProtocolKNXWorldwide standard for home and building automationView profile in smart-building projects. It is the backbone of interoperability in professional HVAC.