via「Google News search」：https://android.gadgethacks.com/how-to/best-hdmi-adapters-turn-your-galaxy-note-9-into-dex-desktop-0186435/

Thankfully, Samsung has revamped and simplified the entire DeX experience with the arrival of the Note 9. Now, all you need to do to get into DeX mode is plug your device into a monitor using a USB-C to HDMI adapter (DisplayPort). From there, you simply launch an app to use your device as a trackpad and virtual keyboard, effectively creating a simplified desktop experience.
There are some minor caveats here, however. If you go with a USB Type-C to HDMI cable instead of the official DeX dock (or the Bixby cable that should be coming soon), you'll be limited to 720p resolution as opposed to the 1080p resolution offered by Samsung's own products. You'll only be able to run up to 5 apps this way, whereas you could run 20 with a first-party DeX adapter. Overall, these limitations are minor compared to the monetary savings you'd get from going this route.
DeX-Compatible USB-to-HDMI Cables
For the reasons stated above, Samsung will naturally advertise its own USB-C to HDMI cable as the best way to connect to a monitor or display, but any adapter of the same type will work.


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