The installation instructions provided with your NMEA^® 0183 compatible device should contain the information you need to identify the transmitting (Tx) and receiving (Rx) A (+) and B (-) wires.

When connecting NMEA 0183 devices with two transmitting and two receiving wires, it is not necessary for the NMEA 2000^® bus and the NMEA 0183 device to connect to a common ground.

When connecting a NMEA 0183 device with only one transmitting (Tx) wire or with only one receiving (Rx) wire, the NMEA 2000 bus and the NMEA 0183 device must be connected to a common ground.