NMEA 2000

Introduction

NMEA 2000 is a networking standard for marine electronics, used by most modern marine electronics hardware. It is is constructed from a a number of devices connected to a single bus, called the network backbone. All devices on the network can both transmit and receive messages.

An illustration of a typical NMEA 2000 network with some example devices is shown below.

Example NMEA 2000 Network.

Figure components are:

1

N2K power cable. Every NMEA 2000 network segment must be connected to boat's 12 V power system. Ideally, the power connection should be roughly in the middle of the backbone.

2

Network male and female terminators. The network backbone must be terminated with 120 ohm resistors for proper network operation. The are mandatory and essential!

3

Drop cables are connected to the backbone using T-connectors. The T-connectiors can have one or multiple drop cable connections.

4

Backbone cables extend the backbone. The maximum length of the network, measured from terminator to terminator, should not exceed 100 m.

5

Drop cables connect individual devices to the backbone. The maximum length of the drop cable is 6 m.

A

A display device such as a Multi-function Display (MFD).

B

A wind sensor.

C

A temperature sensor.

D

An SH-wg device.

The network backbone is shown in pale blue color. All devices connect to the backbone using drop cables. Only one device can be connected to a single drop cable.

At the very minimum, the network must have a 5-way T-connector, two terminators, a power connection, and two devices with their own drop cables.