CAN-FiX (Flight information eXchange)Communications Bus for Avionics and Simulation
CAN-FiX is a set of protocols for exchanging information between aircraft avionics and flight systems. This specification and the protocols themselves are licensed under a Creative Commons license that allows anyone to modify and redistribute these documents without charge. The specification can be downloaded here: http://sourceforge.net/projects/fix-project/files/ This is a community supported endeavour, with the primary goal of providing a standard method for avionics and flight control systems to communicate with one other in a vendor neutral way. CAN-FiX can be discussed at the MakerPlane Forum here: http://www.makerplane.org/forum/viewforum.php?f=24
The specifications and protocols are primarily geared toward the Amateur Built aircraft community. Keeping the specification open and free allows airplane builders to create their own devices and write their own software that will be able to communicate with other devices without need to pay for specifications or licenses. It also encourages collaboration in the development and improvement of the protocols themselves. Corona uses the CAN-FiX protocol for information exchange between avionics systems and within it’s simulators.
FIX is a protocol family. CAN-FIX is a CAN specific implementation of the FIX protocol. CAN® stands for Controller Area Network. It was developed originally as a robust message based protocol for use in automotive applications. It has spread to other uses as well and is now found in medical equipment and industrial controls. CAN is a message based, producer / consumer type protocol that involves one node producing messages onto the CAN-bus and all other nodes receiving or consuming those messages. See the References section on page 81 for more detailed information on CAN.
CAN occupies most of the Physical Layer and all of the Data Link layer of the OSI model. The physical connection is not specified. CAN-FIX will fill in the physical connection specification as well as the Network, Transport, Session and Presentation Layers. CAN-FIX is a much simpler protocol than is described by the OSI model so the correlation is not perfect, but it helps in the discussion.