For example, the NMEA publicizes which messages exist and which fields they contain, but they do not disclose how to interpret the values contained in those fields. Although the NMEA divulges some information regarding the standard, it claims copyright over the standard and thus its full contents are not publicly available. The NMEA 2000 standard was defined by, and is controlled by, the US-based National Marine Electronics Association (NMEA). The interconnectivity among instruments in the network allows, for example, the GPS receiver to correct the course that the autopilot is steering. NMEA 2000 is meant to be "plug and play" to allow devices made by different manufacturers to communicate with each other.Įxamples of marine electronics devices to include in a network are GPS receivers, auto pilots, wind instruments, depth sounders, navigation instruments, engine instruments, and nautical chart plotters. It also allows the instruments to work together, since they share data. This allows one display unit to show many different types of information. The backbone powers each instrument and relays data among all of the instruments on the network. Various instruments that meet the NMEA 2000 standard are connected to one central cable, known as a backbone. The protocol is used to create a network of electronic devices-chiefly marine instruments-on a boat. Raymarine SeaTalk 2, Raymarine SeaTalk NG, Simrad Simnet, and Furuno CAN are rebranded implementations of NMEA 2000, though may use physical connectors different from the standardised DeviceNet 5-pin A-coded M12 screw connector, all of which are electrically compatible and can be directly connected. The higher-level protocol format is based on SAE J1939, with specific messages for the marine environment.
6 Message format and parameter group numbers (PGNs)Įlectrically, NMEA 2000 is compatible with the Controller Area Network ("CAN Bus") used on road vehicles and fuel engines.