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BFX and OpenBusBFX and OpenBus was a historical free hardware project line connected to the simulator work of ASK-Solutions. It provided a way to connect a computer to physical interface cards for cockpit controls, displays, sensors and outputs.
The project belongs to the same simulator lineage as A340GC, libGC and RDDP. Where A340GC and libGC handled glass-cockpit software, graphics, audio, networking and protocol integration, BFX and OpenBus addressed the physical interface side: how real switches, encoders, displays, buttons, lamps and analogue signals could be connected to a computer in a reusable way.
The OpenBus system used a OpenBus bridge connected to a computer through an RS232 serial port. Behind that bridge, interface cards were connected to a shared OpenBus bus. The bus used CAN-bus electrical levels, while the data itself was sent as RDDP packets over an 8N1 115.2 kbit/s serial bit stream.
This made it possible to connect multiple hardware functions to one bus without treating every control, display or input as a separate custom cable problem. The bus and cards provided a structured way to attach real simulator hardware to the software side of the project.
The OpenBus cards were designed for the practical needs of simulator and cockpit interface work. Different cards could provide different kinds of input and output, including:
Together, these functions made it possible to connect cockpit controls, indicators, displays and panels to software that could understand and exchange simulator state through RDDP and related components.
The OpenBus bus software was written in C for the 80C51 line of microcontrollers. The firmware was made available as free software firmware. This was important because the behaviour of the hardware should be inspectable and adaptable, not hidden inside an undocumented controller.
The schematics and PCB layouts were drawn in UltiCap and UltiBoard, from the UltiMate MS-DOS program suite, and were made available as free hardware. This fitted the same practical philosophy as the software: people should be able to study how the system works, repair it, adapt it and build on it.
OpenBus connected the physical side of simulator work to the software side. libGC formed a bridge between OpenGL, audio, network communication and the RDDP protocol, using SDL to access OpenGL and audio. OpenBus used RDDP on the hardware interface side, allowing real interface cards to be addressed and used from the simulator environment.
This connection matters because a glass cockpit simulation is not complete when it exists only as pixels on a screen. Physical controls, display elements, switches, encoders and indicator outputs are part of how a simulator becomes understandable, testable and educational. OpenBus helped make that physical layer reusable and documented.
BFX and OpenBus fit the ASK-Solutions approach because it treats hardware as knowledge that can be shared. The value of the project was not only that it could drive interface cards, but that the firmware, protocol use, schematics and PCB designs could be studied and preserved.
The project also shows how the foundation approached technical education. A hardware interface is a practical teaching object: it raises questions about electrical levels, serial communication, microcontrollers, firmware, inputs, outputs, timing, documentation and maintainability. By making those layers visible, BFX and OpenBus made simulator hardware more understandable.
BFX and OpenBus belong to a historical free hardware project line. It is no longer a current development focus, but it remains important as part of the foundation’s simulator, free hardware and practical interface history.
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