The BACnet standard 1] defines a communication protocol for information exchange between components of a distributed building automation and control system. The BACnet Communications Dynamically Linked Library (DLL) enables researchers to implement selected BACnet communications, creating an interface for data collection that is easy to use. Researchers can integrate the BACnet Communications DLL (BCD) into existing tools, create a new tool with the BCD, or use the BCD with common data acquisition and analysis tools. The BCD has already been used to collect data in a variety of locations.