Project - NMEA 2000 Network - Part 1

We have been busy with various boat projects, but replacing the 1993 electronics with the new electronics has been one of the more significant projects.  One of my main goals when shopping the boat show for replacements was to standardize on the NMEA 2000 (N2K) data infrastructure for all devices.  So far it has been pretty successful.

Our NMEA 2000 Network Design

I prefer the "best of breed" methodology for choosing electronics, so having a standardized data communication platform with common connectors across various manufacturers has been essential to the success of our mixed breed device installation.
There are some important rules around creating a working NMEA 2000 (N2K) Network.  First the basics.  The N2K consists of a cable run with two and only two endpoints.  This is known as the network "BACKBONE".  The backbone needs to be terminated at each end with a termination resistor.



Almost a NMEA 2000 Backbone with one Drop....just missing the second termination resistor.

Devices are added to the N2K backbone using "TEE" connectors that allow "DROPS" to be added to the backbone.  Basically each device gets a drop off the backbone.  The connections to the tee for the backbone and drop connections use the same connectors as the connection to the device.  The backbone connections of the tee have one male and one female connection.  The drop connection of the tee is always female and the device connection is always male.  Meaning your drop cable between the backbone tee and the device is always a length of cable with one female and one male end.

A Drop Tee (left) connected to a Termination Resistor (right)

So you can easily build your own network with a Tee for each drop, a spool of N2K cable, and a bag of Male and Female N2K end connectors.  There are some more things to consider, but those are the basics for now.  In Part 2 I will get into more of the design of the NMEA 2000 network and the devices being interfaced.  Including using a four port hub to run one drop to the binnacle and branching out to multiple short drops for the devices at the helm.

The 4 Port hub in the center is handy for running one drop for multiple devices

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