The BACnet protocol stack library at SourceForge provides a BACnet application layer, network layer and media access (MAC) layer communications services. It is an open source, royalty-free library for an embedded system, Windows, Linux, or other operating system. Example BACnet client and server applications are included.
BACnet - A Data Communication Protocol for Building Automation and Control Networks - see bacnet.org. For software developers, the BACnet protocol is a standard way to send and receive messages on the wire containing data that is understood by other BACnet compliant devices.
The BACnet protocol stack implementation is specifically designed for the embedded BACnet appliance, using a GPL with exception license (like eCos). The code is written in C for portability.
These details are provided for information only. No information here is legal advice and should not be used as such.