This part of GB/T 28847 specifies the BACnet protocol structure, application layer, network layer, data link/physical layer involved in the data communication protocol in the building automation and control system: ISO/IEC8802 3 ("Ethernet") local area network, data Link/Physical Layer: ARCNET LAN, Data Link/Physical Layer: Master-Slave/Token Passing (MS/TP) LAN, Data Link/Physical Layer: Point-to-Point (PTP), Data Link/Physical Layer: EIA /CEA709.1 ("LonTalk") Local Area Networks, Modeling Controlling Devices as a Set of Objects, Alarm and Event Services, File Access Services, Object Access Services, Remote Device Management Services, Virtual Terminal Services, Error, Denial, and Termination Codes , BACnet regulations, BACnet protocol data unit encoding, application protocol data unit standardized description, consistency and interoperability, BACnet extension, network security and other requirements. This section applies to data communication services and protocols between related equipment in building automation and control systems.