Ethernet on UD-3900 not working

I purchased a UD-3900 this week, and so far it’s been working great, even when limited to the USB 2.0 port on my work laptop. However, I’ve found that I’m not getting the Ethernet connection to work.

I have a Cat5 running from my router (Verizon) to the dock, and the lights on the back of the docking station at the Ethernet port do not light up. I’ve tested plugging the Cat5 cable directly into my laptop and have no problems connecting in that scenario. Is this a defect, or am I missing something?


I had the same symptoms. It turned out my work Ethernet is half duplex and the dock only works with full duplex. The solution is to get a USB 3.0 to Ethernet adapter and use one of the front ports. That works perfectly but uses up one port. The key diagnostic was that it worked on the Ethernet at home but not work.

You might try an adapter - plugable makes them as does cable matters and other manufacturers. Good luck!

I just spoke to a service rep at Verizon. Apparently the routers they supply can operate in full or half duplex, but they are set to “auto” by default, whatever the frak that is. The setting can be easily changed in the router’s admin portal. I apparently need to go in and change all five ports to 1000 full duplex. I will try that out later and report my results.

OK, I’ve gone through a bunch of troubleshooting, and I’ve determined that the issue I’m having is not related to half vs full duplex.

When I plug my Ethernet cable directly into my laptop, the router admin portal shows that the port I’m using is connected and is in Full-Duplex mode. When I take that same cable and plug it instead into the docking station, it says Disconnected, and the lights on the back of the dock fail to light. I’ve tried different ports on my router and have gotten the same result.

So what’s my next step?

Update: I found an Ethernet hub to test. When going from the router to the hub to the dock, it DOES work, albeit slow since it’s an old crappy 10Mbps hub. I guess I’ll grab a cheap switch and hopefully that’ll do the trick.