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I've heard that DisplayPort supports sending HDMI, VGA or DVI signal through its ports by using a passive adapter or cable. If true, how can you check if your GPU or laptop model supports that (or maybe I don't need to check and all devices marked with DisplayPort version X and above output port automatically support that?). And finally how can you activate that feature from your OS (Windows 7 here) and select the signal you want to be sent? Or does the detection of what kind of receiving port is connected somehow detected and selected automatically?

My PC: HP Elitebook 850. OS: Windows 7 64.

  • I don't think any kind DisplayPort sends analog signal, so you need an active converter for VGA anyway. As for HDMI/DVI, it depends on whether the port is a DP++ port: en.wikipedia.org/wiki/DisplayPort#Dual-mode . I am not sure if there's anyway to check it in Windows. In Linux it can be checked with xrandr: there will be two logical DP outputs and in verbose mode you'll see one sends DP singal, one sends TMDS (HDMI/DVI singal). – Tom Yan Feb 9 '16 at 3:55
  • Seems like dual mode DVI isn't possible either – Leo Ervin Feb 9 '16 at 4:35
  • You mean dual-link DVI right? As you can read from the wiki entry, as of DP 1.3, the TMDS signal is compatible with that of HDMI 2.0, with the pixel clock bumped to 600MHz. I guess it can be passively converted to dual-link DVI as well with a proper converter/cable. Not to mention that there are active DP to dual-link DVI converters as well. – Tom Yan Feb 10 '16 at 19:02
  • Alas, my laptop is only 1.2... – Leo Ervin Feb 10 '16 at 21:57
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DisplayPort is compatible through all of these connections via different adapters:


DisplayPort to VGA

DisplayPort can be adapted to VGA with an active adapter, as it does not output an analog signal as standard. Note that most of these do not require additional power, and receive sufficient power to function from the DisplayPort itself.

enter image description here

DisplayPort to DVI

Things get a little more complicated here. DisplayPort does not output a signal compatible with DVI as standard, but can be adapted to do so. The type of adapter required varies based on whether you have Dual-Mode DisplayPort (DP++).

enter image description here

For versions 1.3 and above, or DisplayPort via ThunderBolt, this is always present. You can look for a DP++ symbol (above) by your DisplayPort, it would usually be present if your machine has this.

If you do, you can use a simple passive adapter from DisplayPort to single-link DVI.

enter image description here

For dual-link DVI, or DisplayPort without DP++, an active adapter is required, which may require additional power (Often from a USB port).

enter image description here

DisplayPort to HDMI

Again, this varies based on if you have DP++ or not. With it, you will be able to use a passive adapter.

enter image description here

And without, an active adapter would be required, although these are able to draw the power requirement from the DisplayPort.

enter image description here


Note that when using multiple monitors, you may need to use active adapters depending on the video card and it's capabilities over DP++

Looking at this spec list for your model, your machine is equipped with DisplayPort 1.2. As such, it's not guaranteed you have DP++, but still possible, check the port itself to see if the logo is present. If not, you can still do it but will need an active adapter, although these are usually a little more expensive.

For your other question, the adapters will let DisplayPort know what source they require, and will adapt voltages to make sure the correct signal is coming through. You won't need to change any settings for this.

Useful sources:

https://en.wikipedia.org/wiki/DisplayPort

http://www.startech.com/faq/DisplayPort_Converter_DP_Multi_Mode

  • Yes, this laptop has the DP++ symbol on it. Although looks like I need to order an active adapter if I need to use hi res VGA (more than the default VGA port can output) as well as dual link DVI. Would be nice to know how reliable these active adapters (like the dual DVI) are and whether they are suitable for professional work (multi video projection for talks). – Leo Ervin Feb 9 '16 at 18:41
  • This is odd, I got an active DisplayPort to VGA converter but it's still detected as DisplayPort signal. Is that normal or should it be pure VGA signal coming out? – Leo Ervin Feb 10 '16 at 21:58

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