NMEA2000 Basics

A brief description of the most basic NMEA2000 Network

The image below shows about the simplest NMEA2000 network you can create. An NMEA2000 network requires the following bare minimum

• Two devices that need to communicate with each other. In this case a Chartplotter and a Smart Speed and Depth Transducer.
• The network itself requires a dedicated nominal 12 volt DC power supply, shown below as the red cable
• Each end of the network you are creating requires a "Terminator". 
• Each device requires a "drop" or "Spur" cable to connect it to a "T" connection in the network "Backbone"

Without all of the above, the network will not work correctly, if at all.

What will NOT work, is the direct connection of two devices, without a powered and correctly terminated network.

NMEA 2000® networks have a maximum of 50 nodes allowed on a single network, a maximum network trunk length of 200m and a maximum cumulative drop length of 78m.

For very small installations, a single unit network is available as shown below. This module has the terminators built into the block and a separate 12vdc power cable. This unit is limited to connecting 4 devices in total.