J1939

Documents

The SAE J1939 specifications (recommended practice) can be ordered directly from SAE. The whole specification includes several documents. The individual documents are named according to the OSI/ISO layer model for networks. Thus, for example, all J1939-1x documents describe the physical data transmission layer. The J1939-71 document describes the application layer. The following list includes a selection of the most important documents:

• J1939 – contains a detailed introduction to J1939 and can be used as reference for the other parts. In the constantly-updated attachments, there is also a good overview of the defined parameter groups, addresses, and manufacturer IDs.
• J1939-1x – defines the transmission medium (cable, shielding), connectors, as well as the approved baud rate.
• J1939-21 – describes the basic data transmission mechanisms. Among other things, these are the structure of the CAN identifier and of the data bytes, definition of the transport protocols, the targeted request of information, and the confirmation with the help of acknowledge.
• J1939-71 – describes the application layer and defines all parameters and parameter groups.
• J1939-81 – describes the network management.