NMEA 2000 backbones should have termination resistors connected to which of the following?

NMEA 2000 backbones should have termination resistors connected to which of the following?

• A. Each end of the backbone cable
• B. At every device
• C. At the power source
• D. Only at the center

Answer: (A)

Signals on an NMEA 2000 backbone behave like a CAN bus, so the line must be terminated at its ends to prevent reflections that can corrupt data. The two conductors of the backbone should have a 120-ohm resistor tied across them at each end of the backbone. This end-to-end termination matches the cable’s characteristic impedance and absorbs signal energy as it reaches the ends, keeping the waveform clean as it propagates. Putting terminators at every device would over-terminate and disturb the impedance, while terminating only at the power source or at the center would leave the far end unterminated and still cause reflections. So, termination resistors belong at both ends of the backbone.

Signals on an NMEA 2000 backbone behave like a CAN bus, so the line must be terminated at its ends to prevent reflections that can corrupt data. The two conductors of the backbone should have a 120-ohm resistor tied across them at each end of the backbone. This end-to-end termination matches the cable’s characteristic impedance and absorbs signal energy as it reaches the ends, keeping the waveform clean as it propagates. Putting terminators at every device would over-terminate and disturb the impedance, while terminating only at the power source or at the center would leave the far end unterminated and still cause reflections. So, termination resistors belong at both ends of the backbone.