How to Use a Portable Monitor | One Cable or Two

Using a portable monitor comes down to one question: does your device have a full-featured USB-C port? If yes, one cable carries everything; if not, you’ll connect HDMI for video plus a separate power cable.

Portable monitors are simpler than they look once you understand the two connection paths. The whole setup takes about a minute, and the difference between a clean one-cable desk and a tangle of wires comes down to the ports on your laptop, phone, or console.

USB-C Single-Cable Setup

The best-case scenario is a single USB-C connection that carries video, power, and data all at once. For this to work, both the monitor and your source device need a full-featured USB-C port.

Connect the included USB-C cable from your laptop to the monitor’s USB-C port labeled for video input. Dell’s manuals reference USB3.1 Gen 2, Thunderbolt 3/4, and DisplayPort Alt Mode as the standards that support this. When it works, the monitor powers on and displays your screen without any second cable.

Here’s the catch: not every USB-C port is full-featured. Many laptops and nearly all phones include USB-C ports that only charge. If your device has one of those, the single-cable path simply won’t work.

HDMI Plus Power Setup

When your device lacks a full-featured USB-C port, you connect two cables instead. This is the standard route for older laptops, desktops, game consoles, and any device with only plain HDMI out.

Plug the HDMI cable into the monitor’s HDMI port and your source device. Then connect the monitor to power using the included USB-C power cable and a wall adapter. On these monitors, HDMI carries video only — it does not supply power, so skipping the second cable leaves you staring at a black screen.

Dell’s documentation explicitly lists PS5, Xbox, and Nintendo Switch via its dock as HDMI use cases. Many monitors also include a second USB-C port that is power-only, so you can free up the video USB-C port when running the HDMI path. Check your monitor’s port labels before plugging in.

What about phones and tablets? Some portable monitors support USB-C devices that output video, but not all do. iPhones with Lightning require an additional adapter, and even then, some models simply aren’t supported.

What To Do When The Screen Won’t Turn On

Most portable monitor problems come down to three mistakes, and they’re all easy to fix.

First, confirm you’re using a full-featured USB-C cable. The cable that shipped with your phone or a cheap charging cable may carry power only. If the monitor doesn’t detect video, swap in a different USB-C cable and try again.

Second, check the port. On a dual-port monitor, one USB-C port may be power-only while the other handles video. Plug into the video port.

Third, watch your brightness and volume. If you see either symptom, plug the monitor into a wall adapter.

If you’ve checked all three and still get no signal, the source port on your laptop may not support DisplayPort Alt Mode — check your laptop’s specs or try the HDMI route with a power cable.

These three patterns cover nearly every setup you’ll encounter. If you’re still deciding which model to buy, For a broader look at tested 1080p options before you commit, our roundup of the best 1080p portable monitors sorts through the current field.

One final note on power pass-through: when the monitor charges your laptop, it’s pulling power from the monitor’s own adapter. If the monitor is itself powered by a low-output source, raising brightness can draw more than the input provides, causing the screen to drop out. When in doubt, use the included wall adapter rather than a spare low-wattage charger.