In-Line Termination Resistors are typically used when:

• A. For short runs
• B. For distance less than 2 meters
• C. There are cable runs greater than 6 meters up a mast or tower.
• D. For any network

Answer: (C)

In this bus system, keeping the signal clean is all about proper termination to prevent reflections on the line. NMEA 2000 uses a CAN-like backbone that wants a specific impedance, typically matched with terminators at the ends of the backbone. When cable runs are unusually long or run up a mast or tower, the electrical length increases and the risk of reflections grows, which can distort data on the network. An inline termination resistor helps by providing a proper load along that long run, helping maintain the correct impedance and dampen reflections where the line is extended. For shorter runs, the standard end-terminals at the ends of the backbone are usually enough, and inline terminations aren’t typically needed. So when you have cable runs greater than about 6 meters up a mast or tower, inline termination becomes the sensible choice to preserve signal integrity.