Bidirectional HDMI Switch

As it happens, I often need to use a couple of devices with HDMI outputs and a monitor with just one input at the same time, so I decided to make switching between sources a little easier. I used to solve this with the monitor’s second VGA input. Then I ended up with more HDMI devices and had to use an HDMI-to-VGA converter, but at some point I got tired of that and picked up an HDMI signal switch for myself—and for a review.
So, here’s another little review.



First, why this particular model? I won’t claim I specifically needed a compact size or any fancy features. I just needed a simple switch, preferably one that could handle 4K. I also figured bidirectional operation might come in handy, though that was more of a “bonus.”

The switch comes in a compact white box. At first, the “Audio&Video Converter” label threw me off, but when I turned the package over, I realized it was just a clever bit of packaging—the box is universal.


The package is as simple as it gets: the manual and the switch.


The manual includes a brief description and connection options.


The switch has a black-painted metal case. It looks simple and neat.



There are two HDMI connectors on one side and one on the other. Since the switch is bidirectional, there are no input/output labels, for obvious reasons.
The only control on top is a latching button, though it did stick a little at first. There are also two LEDs indicating which connector is currently in use.


There’s nothing else interesting on the outside, so I took a look inside. The case consists of two halves held together by four screws, while the board itself is secured with just one.


Honestly, after clicking the button a few times, for some reason I expected to find something like this inside :)


Or maybe this, since it’s an imported switch :)


Of course, I was joking above, but who knows—you can expect anything from Chinese “innovators.” For example, I’ve come across reviews of similar-looking switches with relays inside!
Here, switching is entirely electronic: pressing the button simply sends a signal to the switch IC. That button was the one sticking on my unit. I suspect I was just “lucky”; I had to lubricate it a little. And yes, it stuck even with the cover off.


Overall, the build quality is pretty good. The only thing that surprised me was the LEDs, which were soldered in at an angle.


There’s nothing on the underside. You can see a little flux residue near the button, so it was probably hand-soldered, like the LEDs.


The active components are the SD642A0 electronic switch itself and a voltage regulator with a 3.3 V output.


I was curious about which switch IC was used, and a quick search for the marking led me to this chip.
Its full part number is TS3DV642; here’s the datasheet.
It’s a 12-channel switch, rated for HDMI 2.0 and resolutions up to 4K at 60 Hz.


Above, I showed a P2K push-button switch. Functionally, this switch isn’t all that different. The only real difference is the signal frequency it can switch. Among electronic switches, the 561KT3 comes to mind.
Inside the chip are a bunch of single-channel switches, and the control logic simply turns on one half or the other, giving us a switch. The specified transistor resistance is 6.5 Ω for port 1 and 8.2 Ω for port 2. I was a little surprised that the resistance differs.


The example layout in the datasheet differs slightly from the actual one, but not significantly, in my opinion.


And of course, some tests—but first, a couple of ways to use this device.
Option 1, which will be the most useful in my case.
Two devices and one monitor. I didn’t put my main computer on the desk; a TV box stands in for it. A DVR is connected to the second input.

Why do I need this personally? Besides writing reviews, I also spend quite a lot of time setting up computers, DVRs, and so on. My main computer is connected to the monitor’s HDMI input. A VGA cable from the monitor’s second input lies on the floor nearby, and I switch between them using a button on the monitor itself. I even chose a monitor where switching is done with a simple button, like on my old one, rather than through a menu, as is sometimes the case. I have to switch very often, and I really don’t want to navigate the menu every time.
But lately, I’ve been seeing more and more devices without a VGA output. I used an HDMI-to-VGA converter, but it puts an extra load on the device under test and is simply not very convenient.
So, essentially, I’ve set up two HDMI inputs on the monitor, switched by pressing a single button.


Option 2.
Here it’s the other way around: one source and two monitors and/or TVs.
I might find this setup useful too, but probably not anytime soon. One real-world use case would be having a large monitor in one room and a preview monitor in another. Switch to the preview monitor, check that the screen shows what we need, then switch back to the main one.
For example, I did something similar for a school I help out. The computer is in a classroom, while the large TV is in the lobby, about 50 m away (by cable). It’s certainly easier when there’s a computer, but a computer isn’t always what’s being used.
Note that this is not a splitter: it outputs video to only one monitor/TV at a time.


I had no problems with Full HD, and I don’t even see a point in including those tests in the review. But I decided to test 4K separately, and unexpectedly, what helped me was not a 4K TV but a TV box I reviewed recently. The thing is, this TV box can convert a 4K signal to whatever output resolution it’s set to. What’s more, it can not only convert the signal but also tell the source that 4K is supported. That’s how it “accidentally” switched my home computer to that resolution.
On top of that, it also passes CEC control, so I ran two tests: 4K and CEC.

Don’t be alarmed by this setup; I’ll explain. The signal path is as follows:
Beelink TV box (4K output) - switch - Alfawise H96 TV box (Full HD here and below) - video capture device - flash drive.


The second TV box receives a 3840x2160 60 Hz signal from the first without any problems. At the same time, I can control the first TV box via CEC using a keyboard connected to the second TV box.


That’s about everything I wanted to say about this device. In short, it works, and works well. It can switch signals at resolutions up to 3840x2160 60 Hz while passing CEC information. The controls and indicators are very simple, it’s hard to break, and the case is sturdy.
The only downside is that the unit I received had a faulty button.

The store provided coupon GBCNA, which brings the price down to $14.87.

As usual, I’m looking forward to your questions in the comments. I hope you found the review useful.