For the record, i'm not an expert on this marine stuff so here what i say:



Backbone cables are also extension cables yes?
You could describe the extension cable as that....same difference

NMEA 2000 Multi-port T-connector is just a pre-made tree of T connectors yes?
Yes....

Power Isolator Tee - I see that Garmin has this type of Tee but dont see it with Lowrance, i would think that it isolates power to just the Tee......per Garmin website this is how it describes this particular tee: Use our power isolator to ensure sources that could power the bus are separated properly during installation of the NMEA 2000 network


In-line Terminator - same as the male/female terminator that are on the end of the networks, this one is in-line and can "complete" the network......per Garmin website: Use our inline terminator between the backbone cable and your compatible device to correctly terminate the network.

Field Installable - those look like if your end got cut off or you had a some NMEA cable but no ends you can use this to make the ends.....