TESmart HKS401-E23 KVM Review: Check the USB Version

For moving one monitor, keyboard and mouse between up to four machines, this is a well-specified switch at a sensible price. The specification that decides whether it suits you is not the 4K figure on the front of the box — it is the USB version of the hub.

A note on this assessment: researched from TESmart's published specifications for the HKS401-E23, not wired into a multi-machine desk here. See how we test.

The problem it addresses

A work laptop and a gaming desktop on the same desk is now an ordinary situation, and it produces an ordinary mess: two keyboards, two mice, a monitor whose input menu you learn by heart, and a peripheral set that always belongs to the machine you are not using.

A KVM collapses that into one set. Press a button and the monitor, keyboard and mouse all move together. It is one of the few desk products where the benefit is immediate and unambiguous — the broader setup problem is covered in one desk for work and gaming.

How it is specified

HDR

HDR10 and Dolby Vision

EDID

Emulation on each input

HDCP

2.2

Audio

Stereo analogue output alongside HDMI audio

Model

HKS401-E23

Power

5 V DC adapter

Chroma

4:4:4

Inputs

4 x HDMI plus USB

USB hub

USB 2.0

Warranty

1 year, extendable to 3 on registration

Switching

Front button, hotkey, mouse gesture or IR remote

In the box

4 x 1.5 m HDMI and USB cable pairs, IR remote

Resolution

4K at 60 Hz, QHD at 144 Hz, FHD at 144 Hz

Two lines deserve more attention than they get: EDID emulation, which is the best thing on the sheet, and the USB 2.0 hub, which is the worst.

What it gets right

EDID emulation is the feature that separates a switch worth owning from one that will make you regret the purchase. Without it, every machine you are not currently looking at believes its monitor has been unplugged — so it forgets its resolution, collapses its desktop and stampedes every open window onto whatever display is left. With emulation, all four machines see a display permanently and the desktop they return to is the desktop they left.

The video specification is genuinely capable for the price: 4K at 60 Hz with 4:4:4 chroma, which is what text needs to look right rather than smeared, plus QHD and 1080p at 144 Hz, HDR10 and HDCP 2.2.

Four switching methods is more than it sounds, because the useful one differs by situation — a hotkey for daily use, a front button when a machine has hung, and a remote for a setup on a shelf.

Ugly score 6, and it earns it

A black steel box the width of a paperback, with four lit buttons on the front and sixteen ports on the back, and behind it eight cables where there used to be two. The box itself is inoffensive; the cable bundle it creates is the real appearance cost, and it is permanent.

That bundle is worth planning for rather than discovering. Everything the desk section says about routing applies with more force once a KVM is in the middle of it — hiding desk cables without blocking upgrades is the relevant reading, and doing it at installation is far easier than retrofitting it later.

Where it stops being the right tool

The USB hub is 2.0

This is the limitation to decide on. USB 2.0 is entirely adequate for a keyboard, an office mouse, a webcam at modest resolution and a headset. It is not adequate for a gaming mouse polling at 1000 Hz or above, and it will not carry a high-bandwidth capture device or a fast external drive at speed.

The practical arrangement, if the gaming machine is one of the four, is to run the gaming mouse directly into that machine and let the switch handle the keyboard and the monitor. That is less elegant than the product promises and it works.

HDMI only, and 4K only to 60 Hz

A DisplayPort monitor or a graphics card being driven over DisplayPort needs a different model. And while 4K at 60 Hz is a good desktop feed, a 4K high-refresh gaming setup does not fit through this switch — for that machine, the monitor's own input switching remains the answer.

It adds cables to solve a cable problem

Four HDMI leads and four USB leads run permanently to the box, plus a power adapter. Behind the desk, a KVM is a net increase in cabling; the tidiness it delivers is all on the desk surface.

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Who should buy it, and who should not

Buy it if two to four machines share one screen and the peripherals you want switched are a keyboard, a normal mouse and a headset. That is the majority of work-plus-personal desks, and the EDID emulation alone makes it a better experience than the cheap switches it sits above.

Skip it if the only thing you actually need moved is the keyboard and mouse — a plain USB switch does that for a fraction of the price, and the monitor already has input switching built in. That comparison is in USB switch vs KVM switch.

Would we buy it again?

Only if the mouse on the switched ports is not a competitive one. With that condition met it is a capable switch, well specified for its class, and the EDID emulation is worth the price on its own. Without it, you will end up bypassing the feature you paid for.