Which practical step directly verifies the end-to-end bus resistance with terminators in place?

• A. Check the color coding of the cables.
• B. Measure the bus resistance end-to-end with terminators in place (approximately 60 ohms).
• C. Replace terminators with a different resistor value.
• D. Reboot all connected devices to verify network health.

Answer: (B)

The step being tested is directly about verifying the physical termination of the CAN bus. In an NMEA 2000 network, there are 120-ohm terminators at both ends of the main trunk. When you measure end-to-end with both terminators in place, you’re effectively seeing two 120-ohm resistors in parallel, which equals about 60 ohms. This measurement confirms that both terminators are present and that the bus has the correct end-to-end termination, which is essential for proper signal integrity on the route.

Color coding only checks the cable appearance, not the electrical characteristics. Replacing terminators with a different value would alter the bus impedance and wouldn’t verify the actual terminating condition. Rebooting devices doesn’t test or confirm the termination or the physical integrity of the bus.