Have 878c and 788ci hd and the Ethernet is not working between them. I have tried resetting the units, clearing all trip log and waypoints and running the latest software. Did do a continuity test and found the Ethernet cord had continuity for each pin to the other side of the plug. The collars of the Ethernet cord did not have continuity to each other. The 700 series Ethernet adapter was harder to diagnose with the hourglass 4 corner pins had a 1 to 1 relation to the round connector but the middle pin continuity went to the collar of the round Ethernet plug. Is this right? Any help would be appreciated.