USB-C works for PD, not DP

I recently got a new work machine (Lenovo X1 Extreme gen4) and am trying to get it set up with my Spectrum. The Lenovo has TB4 and supports DP over USB-C. It has two USB-C/TB ports. I’m using a certified TB3 cable to connect the laptop to the bottom USB-C port on my Spectrum. It works for charging and connecting to the USB hub, however it won’t send a display signal. When I connect the cable, Windows pops up with a message that “Display connection might be limited”.

Any thoughts? Is there a Windows setting somewhere to enable DP over USB-C?

What is the setting you have on the Spectrum? If it is on High Refresh Rate try switching to High Bandwidth in the OSD settings. You can also try changing the connection from type USB C to Display port or something. Hope that helps.

Thanks. I ended up trying a few different cables and my Cable Creation TB4 cable seems to play nice with both the laptop and the Spectrum. So it’s working with that cable :slight_smile:

2 Likes

Hey, just for the future to help out our other users if they need troubleshooting, do you mind putting in what kind of TB3 cable you were using initially and also what monitor firmware version you’re on?

Best,
Steven

Sure.

Firmware: 1.06
Cable that didn’t work: Dell TB3 cable included with UP2720Q professional monitor
Cable that did work: [Intel Certified] Cable Matters 40Gbps Active Thunderbolt 4 Cable 6.6 ft with 100W Charging and 8K Video - Fully Compatible with USB C/USB-C, USB 4 / USB4, and Thunderbolt 3

2 Likes

I did a quick search and it looks like the included Dell cable will only work with a Thunderbolt video signal, not DisplayPort alt mode like the Spectrum uses.

https://www.dell.com/support/kbdoc/en-us/000126400/dell-up2720q-monitor-with-no-video-while-using-included-thunderbolt-3-active-cable

I believe that TB3 predates USB-C alt modes, which is why there’s a compatibility issue. TB4 is relatively recent and is supposed to support alt modes correctly.

2 Likes

Thanks for digging that up, I had been unable to find any info on the cable.

1 Like