The Controller Area Network, also known as CAN or the CAN Bus, is the infrastructure used for internal networking in modern automobiles. It is controlled through a low level system of controller nodes, each of which broadcast all of their data onto the bus. It is therefore the responsibility of the listener nodes to filter through the noise, and determine what traffic is relevant to their individual needs/purposes.

These nodes communicate with each other in a way that is, for the most part, unreadable and otherwise useless to humans in its raw form. Therefore, a semi-standardized format was developed by Vector GmbH to facilitate interpreting and translating the raw Signal values (from sensors and modules), into human-readable values and units (for gauges and data-loggers).

This is the .dbc format I'll be focusing on in this Wiki and its accompanying canbus repository.

Every auto manufacturer has their own proprietary "dictionary" which contains the mappings of their platform's specific adjustment factors/offsets, labels, and units, used to translate the raw sensor values into meaningful data points.

Sometimes these dictionaries (or "databases", "documents") are leaked online, or sold by a disgruntled (former) employee. In most cases, however, enthusiasts such as myself spend countless hours - usually in their own vehicles - reverse-engineering the translations into .dbc files.

This is very much a work in progress.

1. VERSION
2. NS_: New Symbols
3. BU_: Board Units
   • Syntax
   • Examples
4. BO_: Messages
   • Syntax
   • Attributes
   • Examples
5. SG_: Signals
   • Syntax
   • Multiplexers
   • Attributes
6. BA_: Attributes
   • Syntax
   • Definitions
   • Defaults
7. CM_: Comments
   • Syntax
   • Syntax (scoped)
   • Board Units
   • Messages
   • Signals
8. VAL_: Values
   • Syntax
   • Examples

• Boilerplate .dbc Template
• CANpy Original DBC Specification
• PiSnoop DBC Help
• CAN Format for VBOXII and PRO v4 (pdf)
• J1939 DBC from Haskell.org (dbc)
• CANtool Manual (pdf)