Define a PGN in NMEA 2000 and describe its two main components.

• A. A PGN is a Protocol Group Number consisting of a name and type.
• B. A PGN identifies a data group; its 18-bit identifier defines the data content, and the payload carries the actual values for the message.
• C. A PGN is a physical group node used for network topology.
• D. A PGN is a packet destined for a single device only.

Answer: (B)

A PGN in NMEA 2000 identifies the data content of a message and defines how to interpret the data that follows. It’s an 18‑bit identifier that specifies the data group (what data is included and how it’s structured), while the payload carries the actual values being transmitted in that message. This combination lets any device on the network understand what data is present and how to read it, regardless of which device sent it. It’s not a physical network node, and it isn’t a packet meant for a single device; the PGN is about the data content and its interpretation across the network.