All the J1939 data packets, except for the request packet, contain eight bytes of data and a standard header field which contains an index called Parameter Group Number (PGN). This J1939 PGN is embedded in the message's 29-bit identifier.

All the J1939 data packets, except for the request packet, contain eight bytes of data and a standard header field which contains an index called Parameter Group Number (PGN). This J1939 PGN is embedded in the message's 29-bit identifier.

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