If your product only needs to understand a few of the messages within the SAE J1939 standard, then your DBC file only needs to define the messages your product needs to understand, and all other messages do not need to be defined in your DBC file. Once you have the Digital Annex, you can create a J1939 DBC file containing all or some of the information within it. This Excel file is called J1939DA, or Digital Annex, and can be purchased at the SAE web site here: SAE maintains and sells a Windows Excel file that is used to communicate the technical information needed to create a J1939 DBC file. The Standards Committee assigns many identifiers, names, numbers and formats that are represented in a DBC file, but the file itself is not a product of the SAE.

If we limit the discussion to J1939 DBC files, it is important to understand that the SAE J1939 Standards Committee (formally named Truck Bus Control and Communications Network Committee ) does not maintain or distribute a DBC file of any kind. Although the word database is used in many other places and in many other contexts, when used in connection with CAN data, it’s probably referring to the DBC file. In fact, I recently scanned most of the SAE J1939 standards documents and neither the terms ‘DBC’ nor ‘database’, in the context of the DBC file, appeared in any of the documents.ĭBC is short for ‘database’, and you hear engineers using the two names interchangeably. The SAE J1939 standard is written and maintained with a complete understanding of the DBC file, but the term and details are rarely mentioned by the standard.

Similar standards operate for other bus systems, such as FIBEX database files (.xml) for FlexRay and LDF for LIN (.ldf). Used by the automotive industry primarily, Vector database files (.dbc) have since become the de facto standard for exchanging CAN descriptions. The DBC file type was developed by Vector Informatik GmbH in the 1990s to provide a standard means of storing information described in a CAN network. Specifically, I’m referring to the identification of CAN messages and the translation of the raw CAN data, as transmitted within a CAN frame, to meaningful values and meaningful information. When working with CAN data, it’s never long before the subject of the DBC file is introduced, because this is the most common way to handle identification and translation of the data.

Working with Controller Area Network (CAN) data is for the most part an exercise in understanding formats and translation.

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