CAN-based higher-layer standard for commercial vehicles and mobile machinery.

SAE J1939 is a family of higher-layer and application profiles based on CAN that is especially widespread in the commercial vehicle sector. Central terms within it include PGNs and SPNs, through which data contents and parameters are standardized. For data logging, J1939 is relevant because in trucks, buses, and off-highway vehicles many diagnostic and operational data points run precisely over this protocol.