NMEA2000 to J1939 CAN bus

Quick Facts
  • CAN bus stands for Controller Area Network
  • CAN bus is a twisted two wire pair of communication between deivces
  • J1939 is a communication protocol initially designed for the heavy duty market but is used in marine, on-road and off-road vehicles
  • NMEA2000 or N2K is a communications protocol designed for the marine industry
  • J1939 and NMEA2000 communication can both be on the same CAN bus without interference
 
NMEA2000 spec calls for 5 wires:
  • All that is needed to tie NMEA2000 into the rest of the CAN bus is to connect CAN H and L.
  • 12V and Ground will need to be supplied somewhere on the NMEA2000 backbone to power certain devices.
  • CAN Shield is not necessary in most applications
 
The following devices simplify the connection between NMEA2000 backbone and the J1939 CAN bus:
NMEA2000 Pinout
notion image
Pin
Function
1
CAN Shield
2
12V
3
GND
4
CAN H
5
CAN L
NMEA2000 to Deutsch Adapters
Create your own
If you cut a standard NMEA2000 cable in half to expose internal wires you can create an adapter. Use the below reference for colors to functions.