NMEA 2000 network termination is provided by connecting which resistors?

• A. A single 240 ohm resistor at the center
• B. Four 120 ohm resistors at various points
• C. Two 120 ohm, 1/4 W resistors, one at each end of the backbone
• D. Two 60 ohm resistors at the ends

Answer: (C)

Termination on an NMEA 2000 network is all about matching the CAN bus impedance to prevent signal reflections along the backbone. The backbone is the main trunk that all devices connect to, and proper termination means placing a resistor at each end of that trunk. The standard values are 120 ohms, typically 1/4 watt or larger, one at each end. This keeps the signal clean as it travels the length of the backbone.

So, the correct setup is two 120-ohm resistors, each located at an opposite end of the backbone. Placing other values or locations (like a single resistor in the center, four resistors scattered along the backbone, or two 60-ohm resistors) would not provide the proper impedance and can cause signal problems.