BACnet relies on an object-oriented model: every device exposes Objects (e.g. Analog Input, Binary Output) that contain Properties (Present_Value, Object_Name, Description, etc.).

The BACnet model is built from three building blocks: Objects (functional entities such as sensors, command points or schedules, with 60+ standardised types), Properties (attributes of an Object, e.g. Present_Value, Object_Name, Description, Status_Flags) and Services (operations performed on Objects, such as read, write or COV notification). This is markedly different from KNX, which uses Group Objects bound to Group Addresses with no comparable object-oriented hierarchy.

When reading a PICS, always check the Object_Type list before the Service list: a controller that does not implement a given Object simply cannot expose the data you need, regardless of which Services are supported.