The object identifier of a BACnet device (device id) must be unique internetwork-wide, different vendors use different methods for calculating the device id default value. When integrating devices from different vendors sometimes it become necessary to change a device's default object id.
Third party BACnet devices
If the BACnet device is a Continuum device (bCX4040 or b3), Continuum provides a mechanism for changing the default device id.
For a third party BACnet device, VTS can be used to write to the Object Identifier of the device in order to change the device id. Note that this will only work if the device manufacturer has made the object identifier for the device object writable.
Click here to download VTS
Click here to see the procedure to follow to set a third party device id using VTS.