gefran BDI50 Series User Manual page 168

A3.2 BACnet communication protocol
1. BACnet Protocol Descriptions
BACnet is in compliance with four-layer of seven-layer structure models in OSI (Open
Systems Interconnection) of International Standard Organization (ISO). These four-layer
structure models are application layer, network layer, data link layer and physical layer.
Besides, BACnet is definced by the view of standard "object" and "property." All BACnet
devices are controlled via the property of objects. Every controller with BACnet devices is
considered an object collector so that every controller device can execute different kinds of
functions of objects to achieve the communication control and monitor control.
ISO- 8802-2
(IEEE802.2)
ISO- 8802-3
(IEEE802.3)
BACnet Simple Model
Application Layer of BACnet
Network Layer of BACnet
MS/TP
ARCNET
EIA-232
EIA-485
OSI Corresponding Model
PTP
LonkTalk
App 3-18
Application
Layer
Network Layer
Data Link Layer
Physical Layer