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BFX and OpenBusBFX and OpenBus were successive historical free hardware projects of ASK-Solutions around physical interfaces for simulators. BFX formed the earlier hardware interface; OpenBus was later developed as its successor and extended the concept with a bridge, a shared bus, different interface cards and further integration with the simulator software.
OpenBus connected technically with A340GC, libGC and RDDP. Through RDDP, the OpenBus hardware could exchange data with the simulator environment and connect physical switches, encoders, displays, lamps and other inputs and outputs to the software. This RDDP connection was not part of the earlier BFX system.
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 designing a separate interface for every control, display or input. The OpenBus bus and interface cards provided a structured and reusable way to connect physical simulator hardware to software.
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 technically with A340GC, libGC and RDDP. RDDP provided an important link between them: OpenBus could use the protocol on the hardware-interface side, while libGC and other simulator software could process and exchange the same data within the simulator environment.
This allowed physical controls, displays, switches, encoders, indicators and other inputs and outputs to work with the simulator software without placing those hardware functions directly inside a single application. BFX preceded OpenBus historically, but did not yet provide this RDDP-based connection with A340GC.
BFX and the later OpenBus belong to the technical history of ASK-Solutions in which hardware, firmware, protocols and documentation were developed as knowledge that could be shared. BFX formed an earlier step in connecting physical simulator hardware to computers. OpenBus built on that work with a more extensive bus architecture, interface cards and communication with the simulator software through RDDP.
Both projects also provided a practical environment for technical education. The successive generations of hardware made subjects such as electrical levels, serial communication, microcontrollers, firmware, digital and analogue inputs and outputs, timing, protocol design, documentation and maintainability concrete and open to investigation.
BFX and OpenBus are historical projects of ASK-Solutions. BFX was succeeded by OpenBus, which developed the interface concept further and integrated it more closely with the later simulator software. Neither is part of the current development focus, but both remain important within the simulator, free hardware and practical interface history of ASK-Solutions.
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