External Display via USB-C port

I thought I had seen a topic about this, but I cannot find it.

The product page of FP4 says: “External Display, Video out support via Miracast (WiFi) or DisplayPort (wired via USB-C port)”. I have this monitor https://www.lg.com/de/monitore/lg-38wn95c-w which has a USB-C/Thunderbolt 3 input. It works fine with laptops: I was able to test one Thunderbolt Laptop and one with “just USB-C” (without Thunderbolt). When I connect my FP4, it starts charging (the monitor offers up to 94W) as expected, but nothing is displayed. This monitor is also a USB-Hub. A mouse plugged in to the montor allows me to control a mouse cursor on the FP4 (as expected).

Should there be video displayed automatically? Do I have to enable something? Or will this not work?


I connected my FP4 to two different devices - a Dell Docking Station and a Dell monitor with USB-C input - and in both cases the monitors mirrored the phone’s screen automatically.


Hmm… thanks. So I guess if it is not working automatically, then it just won’t work at all.

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Here are a few ideas for troubleshooting :

  • try using the USB-C cable that worked with your non-Thunderbolt laptop
  • check monitor’s settings for any options related to input source, USB-C/Thunderbolt, resolution, etc
  • check the phone and monitor’s USB-C ports for any bent/broken pins

… and I take it you tried manually selecting the input source using the remote?

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Thanks for your ideas. Yes, the input source is correct. The monitor even detects a new connection and promts me to switch to Thunderbolt. But then it goes to sleep due to a missing signal. And, as I mentioned, the USB-hub is working properly, so I guess the cables are fine. However, the monitor is also not available as a audio device for the phone.
I checked again and I was seemingly mistaken about the second laptop, it was Thunderbolt as well. So I have actually never tried a pure USB-C device with this monitor. Maybe that is the catch. (Even though I was under the impression that Thunderbolt is kind of backwards-compatible to displayport via USB-C.)
If I use a regular USB-C cable that I also use for charging, not even the USB-hub is working. USB-hub only works with the thunderbolt cable.
There is nothing else I can test at the moment, I think…


Just did a test with yet another Dell docking station model that also does DP over USB-C - I have plenty of them at work - and had the same problem as you this time.

Here are the models I have tested :

  • Dell U2421H monitor : display works, phone charges, keyboard/mouse works
  • Dell WD15 docking station : display works, phone charges, keyboard/mouse works
  • Dell DA300 USB/VGA/RJ45/HDMI adapter : display works, keyboard/mouse works, does not charge (this device is not supposed to)
  • Dell DS1000 docking station : display does not work, phone charges, keyboard/mouse works, station’s USB-C cable LED does not light up (as it does with laptops)

489€ on amazon :open_mouth:
I’d be interested in some cheaper alternative that provides all 3 services; charging, display + keyboard/mouse if anyone has an idea :smiley:

We used to buy them 120€ from DELL, and it’s not sold anymore so it’s definitely not worth more than that :wink:

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Thanks for the input.
Any idea what criteria to look for to find a dock/adapter that can charge and display simultaneously ?

Actually, these products from DELL are things I had lying around at work and are overkill for use with a phone. They’re docking stations for laptops, some of them support multiple monitors, etc.
If I had to buy something to connect a phone to a screen, keyboard and stuff, I would rather look at this kind of device (no idea if this specific model works though).

I imagine Samsung Dex compatible docks should work. However, since the Fairphone has no Dex-equivalent functionality, all you’ll get is your phone screen mirrored on your monitor, and not a full fledged desktop environment like what Dex offers.

Ahah funny, I was actually precisely reading this devices page on Amazon when I got your notification. Could be worth trying.
Thanks for the quick answers !

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Thanks for your tests! To reiterate: The Dell DS1000 docking station does not seem to be a Thunderbolt 3 device. So my assumption that Thunderbolt is the problem is not supported by your results.
I hope we can get some more people to test this :slight_smile:

A setup that works for me: some old IIyama monitor with DP, a mini-DP cable, a USB-C to mini-DP adapter, my FP4. Then the screen is mirrored on the monitor.


To those who got it working: are you able to find what resolution your monitor is using?

It might be that an ultra-wide screen does not support the resolution the phone requests.

I have just read the monitor’s manual and its USB-C port can be used to provide a USB hub function, and the manual suggests (but doesn’t explicitly say) that that is what you get if you don’t connect a Thunderbolt device. Could you try connecting a mouse or keyboard to the monitor’s built-in hub and see whether your phone responds to those?

You might get video displayed using the HDMI/DP input and a converter cable if Thunderbolt is indeed the problem, but then you can’t charge off the monitor.

So… the last reply promted me to take another look. And after having already tested the default Thunderbolt 3 cable (that came with the monitor) and a USB-C cable, I realized I had one other Thunderbolt 3 cable lying around. I tried it with the FP4 and everything worked: Mirrored display, power, USB-hub mouse input. With about 50 cm length, the working Thunderbolt cable is much shorter than the not-working cable. That is the only difference I can see from the outside.

Yay! I am glad it is actually working. I don’t really plan on using it much. But hey, maybe somewhere down the line Android will have a better deskop experience, not just a mirrored screen. And then my hardware is ready for it :slight_smile:


So I thought i owed to report after receiving this dock.

I plugged my phone on it and instantly got: display + mouse + keyboard + charging device working.
But then funny things happened.
I was kind of happy but frustrated to be stuck to portait mode while navigating in menu, browser etc. as the dock isn’t made to rotate the device.
So I installed an app to force changing orientation and it started messing up with resolution:

  • external hdmi display was suddenly all pixelated, like 480p or something
  • device screen was suddenly weirdly displaying font smaller, as if DPI was changed although no modification was made whatsoever.

I ended up unplugging the device, uninstalling the orientation-forcing app, when I plugged it back:

  • hdmi display wasn’t working
  • mouse + keyboard wasn’t working
  • device was charging

Only solution was to reboot the device.
In the end I found out installing the app “SecondScreen” was the best way to use this feature.
It allows you to create profiles that will automatically set custom DPI and desired screen orientation when a second screen is plugged.


I tried to plug my FP4 to the two models of docking station we have at work, but unlucky me: the FP4 charges and that’s all :frowning: . No screen mirroring…

  • ThinkPad Thunderbolt 3 Dock (link)
  • Gearlab Triple 4K Display dock (link1, link2)

I didn’t try several USB-C to C cables, only the default one of the docking station, that works well for my laptop…

Is there anything that I could look at ? Like some developer option?

Didn’t find any relevant result looking on internet for “docking-name + android”, is it a possibility that those aren’t compatible?