The most common mistake we see is terminator usage, be that only one present, or having more than two present. There should only be 2 NMEA 2000 Terminators on a network, one located at either extremity of the backbone (in-line terminators are an exception to this). The terminators act as a resistive load to correctly terminate the network and help to reduce reflections of signals.
A correctly terminated network will have a resistance of 60 Ohms on the backbone, which can easily be tested using a multimeter. A quick indication that something is wrong is if the resistance is 120 or 40 Ohms. 120 means that there is only 1 terminator present and 40 means there is 3. This issue is very frequently seen when using devices that have internal terminators. These terminators operate exactly the same as your common external one and should be treated as such.
