FSD is a flight simulator multiplayer server program. It started with the C++ version (fsd1110) released on the Apollo 3 forum. It was then iterated by major flight simulation organizations, and many derivative versions appeared, but the basic protocol instructions were still compatible.
Unfortunately, the derivative versions of major flight simulation organizations are not open source, which makes the current FSD Based protocol gradually closed.
This project is a Java implementation of the fsd1110 version. Thanks to the simpler programming paradigm of Java, for those who are not familiar with C++, you can start to understand the FSD protocol from this project.