Linear Backbone Construction

The backbone is the main communication path of the NMEA 2000® network, so it is extremely important to construct the backbone properly. An improperly constructed backbone may prevent the network from functioning, or you may experience unexpected performance.

The backbone consists of a combination of T-connectors and cables, terminated on both ends. All T-connectors must connect to the sides of one another either directly or through a backbone cable extension. The top of a T-connector is used to connect a device or power to the network only, and the backbone cannot route through the top of a T-connector.

Figure 1. NMEA 2000 Network with Correct Linear Backbone Construction

Correctly-constructed NMEA 2000 backbone example with callouts

Callout number one

Female terminator installed correctly

The terminator must connect to the side of the last T-connector in the backbone.

Callout number two

NMEA 2000 devices and power

NMEA 2000 drop cables and network power cables must connect to the top of a T-connector, and never to the sides.

Callout number three

Backbone cable

If needed, the backbone can be extended using a cable connected to the sides of a T-connector.

The maximum length of a single backbone cable is 100 m (328 ft.)

Callout number four

Male terminator

The terminator must connect to the side of the last T-connector in the backbone.

Figure 2. NMEA 2000 Network with Incorrect Linear Backbone Construction

Incorrectly-constructed NMEA 2000 backbone example with callouts

Callout number one

NMEA 2000 devices and power

NMEA 2000 drop cables and network power cables must connect to the top of a T-connector, and never to the sides.

Callout number two

Male terminator installed incorrectly

The terminator must connect to the side of the last T-connector in the backbone, and cannot connect to the top of a T-connector.

Callout number three

Female terminator installed correctly

Callout number four

Backbone cable installed correctly

Callout number five

T-connector installed incorrectly

T-connectors must connect to one another using the sides only, never the top.

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