Review: BENFEI Wireless USB C to HDMI

The good folks at Benfei have sent me another gadget to play about with. This one comes in two parts. The first plugs into an screen's HDMI port, the second beams video from your device's USB-C port across the airwaves. Here's what it looks like:

But how does it perform? Plug the HDMI into your TV and its USB-A end into a suitable power source (my TV had one nearby).

After a few seconds, my TV displayed this splash-screen.

The QR code appears to be vestigial. It tells you the Wi-Fi details of the device, but the USB-C dongle is pre-paired. I plugged the dongle into my Linux laptop and, a few moments late:

Success! It works pretty damn well! The resolution was 1920x1080, stereo sound was clearly separated and was in sync, video quality was reasonably smooth.

There's a pass-through USB-C charging port on the side of the dongle. It will only do 40W - so you don't get ultra-fast charging, but it should be more than sufficient for your average laptop.

It claims a range of 30 metres. My house isn't that big. Once I was about 5m away, video and audio started getting stuttery. A message popped up on screen suggesting changing Wi-Fi channels. For basic presenting, it was absolutely fine while at the other side of the house.

Linux Compatibility

This worked instantly with Linux. Somewhat uninventively, it does not present as a USB-C device! You'll see nothing in lsusb - instead, it shows up as a screen:

As it is just another monitor, you can either extend your desktop to it or mirror your main screen.

Similarly, it presents as a generic audio device:

You can route stereo audio to it.

Android Compatibility

Android's DP Alt Mode support is still a bit shaky. Nevertheless, this Benfei dongle worked! The screen was auto-detected and I was able to play audio without any problems.

Screen mirroring worked - so I could view my apps on the big screen.

Note that if your screen isn't 16:9, you'll get black bars to maintain the aspect ratio. I think that's an Android limitation.

It is hard to take a photo of a TV and have it look good - but, please rest assured, the colours looked exactly as expected.

Playing video and audio worked fine.

Technical Background

The QR code it presents gives an SSID and a (base64 encoded?) password. It says it is a softap which makes me think this is ESP8266 powered. It also seems to advertise KOM.to - whose products come from EZCast.

The HDMI dongle presented both 2.4GHz and 5GHz Wi-Fi networks - both with hidden SSIDs. Given the power draw of a typical USB-A port, they weren't overly powerful, but got the job done. There's no way to update firmware on it that I can see.

Downsides

These are some minor quibbles.

The dongle only has an LED on one side. It will work either way up, but you won't see the status light if you plug it in upside down.

While video quality is excellent, it is limited to 30fps. It will take a 60fps signal, but there's only so much data you can squeeze over a wireless connection.

The USB-C dongle gets warm during use. Nothing too hot - but it was surprising to me just how quickly it heated up. There are plenty of grilles on the casing to let the heat out.

The USB-A cable is a bit less than 1 metre. That's fine if your screen has a socket - but you might need an extension if not.

None of these are show-stoppers. Just something to be aware of.

Verdict

For slideshow presentations, this is excellent. No faffing around or software to install - just proper plug and play.

For watching videos, it is good enough. Perfect for streaming your laptop or phone to a hotel TV.

The Benfei Wireless USB C to HDMI kit retails at around £56. I think that's fairly reasonable for a bit of kit like this. It comes with its own hard-shell carry-case to protect it. It is light enough to throw in your bag as a "just in case" item. If you're regularly presenting on other people's monitors, you'll know what a pain it can be to get right - this simplifies everything. USB-C means no looking for adapters on your side, and every monitor seems to come with a USB-A socket for power.

Thanks to Benfei for the review unit.