AX.25 is a layer-2 networking protocol, originally designed by amateur radio operators for use in the amateur radio spectrum.
Besides the de facto VHF and UHF packet exchange protocol for amateur radio operations, AX.25's reliability and robustness has allowed it to find successful deployments in other venues as well, including the aerospace industry, military installations, and more. Indeed, it seems as if AX.25 is used more by non-amateur users than by amateur radio operators themselves!
As a member of the AX.25 Layer 2 Special Interest Group, one of the problems that is often encountered is that nobody wants to support AX.25 when there are already pre-existing libraries for IP. These libraries, typically wrapped in a BSD Sockets API, allow for relatively effortless networking capability without having to constantly re-invent the wheel. Moreover, BSD sockets is more or less platform independent, with versions available in some capacity for Windows, Unix, AmigaOS, OS/2, et. al.
OpenAX.25 is a project that is growing out of the need for having a flexible AX.25 implementation that is open, portable, easy to administer, easy to write applications for, and is easy for the user to use. Ideally, it should be scalable for use in embedded as well as desktop applications. The goal of OpenAX.25 at this point is to serve as a reference implementation for the AX.25 Layer 2 SIG, as well as to foster further exploration of layer 1 and layer 3 networking designs. For example, I wanted OpenAX.25 to be able to handle the use of both hardware and software modems, especially experimental ones, as well as AX.25-over-IP tunneling.
Although coded to use a Posix environment, I do not see any immediate reasons why it wouldn't be possible to port it to Windows environment either. I do not have or use Windows, so I must rely on contributions of patches to make sure that the Windows builds are up to date. Indeed, by porting it to foreign environments, more and more of the program's logic can be kept modular against OS-specific logic.
This project website, and the software described herein, is maintained using the Darcs revision control tool. Contributions and corrections to the website are encouraged via Darcs patch submissions.