-1

This is 2019.

Is there any adapter that can display the video signal of a HDMI/DP device like a tv-box, PC or Notebook to a thunderbolt 3 Display?

The other way around doesn't count.

Edit: Delock has made it! It should be at least compatible with all USB-C Alt mode compatible displays.

They also have good HDMI male to DP female adapters with an extra usb for power on the HDMI side, not at 4k@60hz like on the first cable, but still.

1

Revised Answer:

After taking a closer look at USB-C or Thunderbolt 3 and how they achieve video output, I don't think an adapter exists to connect an HDMI video source to connect to a USB-C display. Even the official HDMI website shows the conversion as being one-way: USB-C to HDMI.

A major caveat is that sending HDMI over USB-C requires the video source to send additional signals that are not part of the HDMI specification; They're part of the USB-C specification.

For conversion in this direction to work, an adapter would have to be a USB-C Host controller and signal to the monitor that it wants to use the HDMI alternate mode. Creating a video adapter that acts as a USB-C host device is not trivial, and almost pointless since most devices or screens have multiple video connectors to use instead.

I believe that it may be possible to make such an adapter, but the demand for it is too low for any to exist yet.


Old Answer:

"This is 2019." Yes, but new video connectors don't always make things simpler.

To answer your question seriously, the thunderbolt 3 (USB-C) connection uses a DisplayPort signal for video. Unfortunately HDMI to DisplayPort (in that direction) is not compatible with just a simple wire-to-wire converter. You actually need something known as an "Active HDMI to Displayport Adapter", and obviously the displayport side needs to be the USB-C connector.

I am also fairly certain that the USB-C monitors get their power from the USB-C connection. If you have a monitor like that, the adapter would have to supply power too!

I have never seen an adapter that meets all of those requirements so I cannot recommend one for you.

It might be possible to combine two adapters:

  1. HDMI -> DisplayPort
    This one must be active, so requires its own power usually from USB.
  2. DisplayPort -> USB-C
    This one may be VERY hard to find in this direction but theoretically possible. (It probably doesn't exist.)

Old Update:

It turns out that I entirely missed that USB-C (and thunderbolt 3) can output HDMI signals too (as an Alternate Mode on top of USB-C). That implies that USB-C displays (but not necessarily ones that require Thunderbolt 3) can accept HDMI signals through that connector. This raises some hope that there is a passive HDMI to USB-C cable/adapter out there. (This isn't possible without negotiating the video mode over USB first.)

| improve this answer | |
  • 1
    @KevinCrans, I'm reading elsewhere that a passive HDMI <--> USB-C cable did not work with an HP portable monitor, it will depend on the portable monitor you're using whether the passive cable could work, since some USB-C inputs don't accept HDMI. (I presume the ones that call themselves thunderbolt displays?) – Romen Aug 30 '19 at 14:46
  • 1
    @KevinCrans, No info sorry. Here's the question on SuperUser that could actually be considered a duplicate of this. I suspect that HP screen just doesn't support HDMI over USB-C, but it might be hard to find since Thunderbolt and USB-C defined the DisplayPort mode first. Monitor manufacturers will probably opt for that as the "default" mode assuming the output is a USB-C port on the PC too. – Romen Aug 30 '19 at 15:07
  • 1
    Actually the power can go both ways... There are enterprise-class displays which also work as USB hubs all the while charging your notebook. All over a single USB-C cable. – Jan Dorniak Sep 9 '19 at 1:52
  • 1
    HDMI does not output power. So something like a laptop or TV box would not send power over an HDMI --> USB-C adapter. As mentioned earlier, this means the USB-C display would need its own power cable. Since this is a very unusual use-case for HDMI and USB-C, there just isn't any demand or reason to make an adapter that goes HDMI to USB-C for only video. People who buy that adapter might try to use it backwards and return the product in frustration because their USB-C or TB3 port wouldn't output HDMI video without a proper USB-C device on the other end. – Romen Nov 10 '19 at 13:29
  • 1
    @KevinCrans, USB-C displays are almost exclusively intended to be used with laptops that have USB-C. Connecting them to other devices is not an expected use-case, and if too few people want to use the product that way, manufacturers won't consider it profitable to support those users by implementing non-standard functionality. (Like passive HDMI over USB-C) Also, USB-C can output 100W of power so it is often used for charging laptops and portable displays with batteries. – Romen Dec 10 '19 at 21:02
1

Looks like Delock has made one explicitly called USB-C to bidirectional DP Alt mode Cable! Everyone, hooray for Delock!

| improve this answer | |
  • 1
    This may work for many USB-C displays, but anyone looking at this recommendation should know that the cable does not support DisplayPort to Thunderbolt 3. DisplayPort via Thunderbolt-3 (on a USB-C connector) and DisplayPort Alternate Mode via USB-C are different video signals! – Romen Mar 3 at 18:04
  • Thank you for sharing your intel with us, TB3 is backwards compatible with USB-C Alt mode right? What you're saying is funny, because of how Virtuallink is different. – Kevin Crans Mar 4 at 14:49
  • 1
    Thunderbolt 3 hosts are backwards compatible with USB-C, that is correct. But Thunderbolt 3 displays may be expecting a thunderbolt-format DisplayPort signal. It is possible that some "Thunderbolt 3" displays do not support USB-C Alt-Mode at all, because Thunderbolt 3 itself provides an alternative DisplayPort implementation. – Romen Mar 4 at 14:59
  • 1
    And VirtualLink is a USB-C alt mode. Not related to TB3 at all. Right now mostly video cards and specific ports on gaming laptops have support for VirtualLink, not all USB-C outputs! – Romen Mar 4 at 15:01
  • Good thinking! And thanks for sharing that last one as well, didn't got a clue. – Kevin Crans Mar 4 at 15:04

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.