NMEA 2000 is a single-bus architecture that uses differential signaling and three independent cable shields in an attempt to improve noise immunity in the nautical environment. NMEA 2000 is a true bi-directional network, unlike the previous NMEA 0183 which was just a single-talker, multiple-listener serial interface
NMEA 0183 operates on a 1-to-1 connection method using RS232/RS422, where multiplexers and buffers are required to connect multiple devices 'together'. NMEA 2000 uses CAN with a backbone/drop cable network system, where all devices on the network talk to one another.
