BACnet Terms

BACnet: Building Automation and Control NETworking protocol (ANSI/ASHRAE Standard 135-2004) are open communication protocol standards conceived by a consortium of manufacturers and system users under the auspices of ASHRAE. Data is created as a common set of “objects”, which can be accessed using a standard set of “services.”

BACnet client: operation mode for the BACnet system or device, where it makes use of the BACnet device for some particular purpose via a service request instance.

BACnet server: operation mode for the BACnet system or device, where it provides a service to a requesting client.

BACnet/Ethernet or B/ETH: BACnet over Ethernet, one of the original BACnet link-layer types. Since the introduction of the BACnet/IP, its usage has become less common.

BACnet/IP or B/IP: BACnet over Ethernet IP. Introduced in “Annex J” of the BACnet standard, it has become the most popular BACnet link-layer protocol.

BACnet MS/TP or MS/TP: BACnet link-layer protocol used by lower-cost devices, using master-slave/token-passing over RS485 multidrop networks.

Object Identifier or Object ID: BACnet method to identify a particular object within a device, using a combination of its object type and an instance number (unique for that type, within that device). In case of the single Device Object (type) per BACnet device, it must have a unique instance number across the BACnet network on which it is installed.