BACnet is a communications protocol for building automation and control networks. It is an ASHRAE, ANSI, and ISO standard protocol.
BACnet was designed to allow communication of building automation and control systems for applications such as heating, ventilating, and air-conditioning control, lighting control, access control, and fire detection systems and their associated equipment. The BACnet protocol provides mechanisms for computerized building automation devices to exchange information, regardless of the particular building service they perform.
Specifically for Paradigm LightDesigner, when creating a configuration for a Server Project, BACnet is a supported feature. See also related topics: BACnet Interface, Configuring BACnet I/O and BACnet PICS.