Video Cables Untangled

Justin_smallMany Plugable products, like our USB docking stations and USB video adapters, allow you to connect additional displays to your system. However, deciding which cable types to use for those displays can be confusing. I will try to clarify the situation in this post.

The image below shows the back of our UD-3900 USB docking station. Let’s use it as an example.

Video outputs of the UD-3900 USB docking station

Video outputs of the UD-3900 USB docking station

I’ve labeled the UD-3900’s two video outputs. One is a HDMI; the other is DVI. When designing this dock we put a lot of thought into these outputs, wanting to give our customers as many options as possible for connecting different displays. We arrived at these two because many types of cables can be attached. Let’s look at a few examples.

The most commonly used cables are standard DVI and HDMI cables (photos below). “Standard” means the cable has the same connector on each end. These cables should always work with the dock as long as the cable itself is not faulty. When troubleshooting a display problem, the first step is to check that the cables are connected securely and if possible swap them with ones that are known to be good.

Standard DVI to DVI cable

Standard DVI to DVI cable

Standard HDMI to HDMI cable

Standard HDMI to HDMI cable

There are other options besides standard HDMI and DVI cables. A DVI to VGA adapter is included with the UD-3900 that can connect the dock to an older monitor with VGA inputs using a standard VGA to VGA cable.

DVI to VGA adapter, two shown so both connectors can be seen

DVI to VGA adapter, two shown so both connectors can be seen

Although not included with the docking station, you can also use an HDMI to DVI cable to connect a DVI display. Although we don’t make a cable like that ourselves, many of our customers have successfully used one like this: www.amzn.com/B00K7HECTQ/

A nice thing about this type of cable is that it is bidirectional, which means it can work in both directions. It can go from the HDMI port on the dock to the DVI input of a display or from the DVI port on the dock to a HDMI display. If needed, you can also use Plugable’s optional HDMI-VGA cable (http://www.plugable.com/products/hdmi-vga) to connect the HDMI port to a VGA display.

So what does this all mean? Out of the box, our UD-3900 dock can connect three types of displays: HDMI, VGA or DVI, and by using various cable and adapters you can
adapt these outputs to your particular setup. You can have two HDMI displays, two DVI displays, two VGA or any combination of those.

Now that we have seen what does work, how about some examples of what does NOT work?

I mentioned earlier that you can convert the HDMI output to DVI and vice-versa, but there is an important point to note: HDMI output can carry an audio signal, but DVI output cannot. Why does this matter? If you convert the HDMI output of the dock to DVI you will lose the audio. By the same token, if you convert the DVI output to HDMI, it cannot carry audio as that information was not present to begin with.

There is a common misconception about converting HDMI to DisplayPort. Although there are simple cables with an HDMI connector on one end and a DisplayPort connector on the other, they will not work with Plugable docking stations. This is because they are usually passive cables that only convert DisplayPort output to HDMI and not the other direction. Differences between the two standards only allow for this unidirectional conversion.

Although somewhat complex, I hope this information will help untangle the many cabling possibilities when using our products. Please let us know if you have any questions in the comments below!

6 comments on “Video Cables Untangled”

  1. Marty Reply

    I think it would be most helpful to see how to connect two DVI 23″ Monitors to the Plugable USB 3.0 Docking Station w/Dual Monitor Support.

    • Bob Boerner Bob Boerner Reply

      Hi Marty,

      I speak to that scenario in the post. To add two DVI displays you would use one DVI to DVI cable to connect from the DVI output of the dock to the DVI input of the first monitor. You could then use a HDMI to DVI cable like the one I link to in the article (http://www.amzn.com/B00K7HECTQ/) to connect from the HDMI output of the dock to the DVI input of the second monitor.

      Thank you,

      Bob
      Plugable Technologies
      http://www.plugable.com/support

      • Marty Reply

        Thanks Bob for the quick response.
        If I understand correctly I do not need to purchase a Plugable USB 3.0 DVI Video Graphics Adapter but rather a Cable Matters® CL3 Rated High Speed Bi-Directional HDMI to DVI Cable?
        This solution will allow me to connect my Lenovo Yoga Pro 2 to the the Plugable docking station and drive both monitors?
        Thanks

        • Bob Boerner Bob Boerner Reply

          Hi Marty,

          Assuming both of your displays have a DVI input available, yes you would only need to purchase our UD-3900 docking station with dual monitor support and the Cable Matters HDMI to DVI cable to connect both displays. This assumes of course you already have one standard DVI to DVI cable.

          Thank you,

          Bob

          • Marty

            LOL that would have saved me $30, I ordered your Plugable USB 3.0 DVI Video Graphics Adapter.
            I will order the Cable Matters® CL3 Rated High Speed Bi-Directional HDMI to DVI Cable to see which one gives me the best performance. I gotta say your product is the only one that works as advertised. My Lenovo Yoga Pro 2 has been a challenging to find a docking station that plugs into the laptop and works with out purchasing additional cables and spending hours to make every thing work. I will be telling all my colleagues about your product. I travel for my job as an Oracle consultant and I like the ultrabook platform but require a solution when I get home to efficiently sync my files with my NAS. Thank you

  2. Bob Boerner Bob Boerner Reply

    Hi Marty,

    We have a 30-day no-hassle return policy, so you have the option to return the extra adapter for a refund. Thank you for the kind words about our products, they are much appreciated.

    Bob

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