Device Access Object Mapping refers to how BACnet objects are represented in Device Access in the form of Functional Items.

A router or a gateway can be the end device, that has a number of objects which get mapped to the BACnet objects. Device objects are the functionalities according to the BACnet specification.

Once you have connectivity to the devices you can control them. Applications work with Functional Items (FIs) and OSGI/Functional Items Management (FIM) events. Properties which are eventable (e.g. temperature changes) are not readable nor writable.