BITXml is an open xml based protocol for Machine to Machine communications. BITXml is both language and "transport" agnostic and covers all the requirements of a generic M2M telemetry & control application. For more info www.bitxml.org
CanFestival focuses on providing an ANSI-C platform independent CANOpen stack that can be implemented as master or slave nodes on PCs, Real-time IPCs, and Microcontrollers. A WxPython based CanOpen Object Dictionary editor GUI is also provided.
SerialPortNet is an open source serial port communication library for Microsoft .NET. It's written in c#, implements complete .NET 2.0 specifications, and is designed to allow for multiple OSes and add-on 3rd party Serial to Network adapters.