8KSW21DP-DM issues


I’ve had an 8KSW21DP-DM for about 6 months and have always had issues with frequently losing the video signal to one or more screens for a few seconds at a time. Due to my MST setup (see below) I thought this may be down to the DP cables supplied with the KVM so upgraded these to DP 2.0. This made no difference (except to my bank account). The displays can sometimes be stable for a couple of hours but at other times one or more of the screens can go black for a few seconds, then displaying the images again for a fraction of a second before going black again and repeating this over and over. This seems related to what’s being displayed on the other screens as the only way to get out of this cycle is to close or minimise any open windows. If I connect the monitors directly to either PC using any combination of cables everything works perfectly.

Switching between PCs has never been close to the advertised 2-3 seconds switching time. It’s generally 10-15 seconds. While this is annoying I can live with it, however recently every time I switch between my two PCs whichever PC I’m switching away from immediately reboots losing anything I’d not saved. This happens both ways, ie. PC1 switching to PC2 causes PC1 to restart, and PC2 switching to PC1 causes PC2 to restart.

My Setup is:
2 x PCs both running Windows 10 Pro.
4 x Dell P2723DE monitors running at 2560 x 1440 (59.951 Hz).
2 of the monitors are connected directly to the KVM switch and the other 2 monitors are daisy chained to these using MST.

Hello Iwal,

This is technical support,we are truly sorry for the issues.
Please help update the new firmware to have a test: https://we.tl/t-p4HuLUZIhZ
Then,could you try disconnect the MST setup and keep only two monitors connect to KVM for a check as well?
Where you purchased this product and what is your order number?
Best Regards,

Hi Kevin, I’ve updated to the new firmware and I’m still seeing the same issues as before. However when switch from PC2 to PC1, PC2 resets as it did previously but now the KVM also doesn’t sync correctly with the monitors, so eventually the monitors go into standby because they have no signal from PC1. If I turn off the KVM then turn it back on it then syncs correctly and display’s PC1 output.

Hello Iwal,Could you try dieconnect the MST connection for a check?
And what is your order number?

I’ve just tried without MST connected and it all seems to work correctly, even the switching time is now around 3 seconds.

I bought this switch specifically for the MST support so I hope this problem can be solved.


One of the screens has just started going black again. This is while running two monitors connected directly to the KVM, so MST is not involved this time.

Could this all just be a faulty KVM, or are these known issues with this model?

Hello IWal,

We are truly sorry for the issues.
we have another similar model which come with 3x DP for each computer and output with 3 monitors,it is our iDock D23. This new model come with the higher performance than 8KSW21DP-DM.
After discussed with engineer and they recommend to use iDock D23 in your setup:

Thanks for the update Kevin.

I’m not happy that the switch I have isn’t actually up to the job, even though your online documentation suggested it should be capable of doing what I needed it to do, and now I’m being advised to buy an alternative (more expensive) model. What makes this even worse is I followed the recommendation on the products web page to upgrade the cables to 2.0 certified ones if there was screen flicker, costing me even more money.

As the existing switch is effectively of no use to me am I able to return this to offset against the cost of a new one?

Hello there,

Yes,please submit the RMA form: RMA Request Form - AV Access
Then our customer service will hellp to follow up with you and make the refund for you,and you can place the new order for our new iDock D23.
Truly sorry for the inconvenience with you.

Thank you Kevin, it’s great to see such good customer support.