USB-C to DisplayPort: does it work, and what is Alt Mode?

What DP Alt Mode means

DisplayPort Alternate Mode is a feature of the USB-C specification that allows a USB-C port to output a DisplayPort video signal. The port has to implement it - the cable does not add this capability. If the source device does not support DP Alt Mode, a USB-C to DisplayPort cable will not output video, even if it fits.

How to check your laptop

Look up your laptop's spec sheet on the manufacturer's site. Search for "DisplayPort" or "DP Alt Mode" in the connectivity section. If the USB-C port specs list "DisplayPort over USB-C" or "USB-C with DP", you are clear. Many recent MacBooks, Dell XPS and HP EliteBook models support it. Chromebooks vary - check per model.

Direction and resolution

USB-C to DisplayPort is one direction: USB-C source to DisplayPort display. You cannot run it the other way (HDMI or DP source to a USB-C display - that is a different cable). The maximum resolution depends on your laptop's DP Alt Mode version: DP 1.2 carries 4K at 60Hz; DP 1.4 carries 4K at 120Hz and 8K at 30Hz.