The screen of my graphics tablet is not detected

Hello
Your tablet must be connected with a video cable (SVGA if I remember correctly) to your computer to be managed.
However, your computer must handle the VGA output (DB15, blue in color) independently from the connector where your main screen is plugged in.
How are you connected for your main screen?
What is your computer brand and model?
What operating system?
A+
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If the answer helped you, a little thank you is really nice...
Is it resolved? The green button at the top, that's great!

Let anyone who has never opened a user manual throw the first mouse at me ;-)

Hello
Are you sure that your video card supports both HDMI ports simultaneously?
Try replacing the tablet with your TV!!
Try a test with just the Tablet on HDMI!!
See you later
--
If the answer helped you, a little thank you would be really nice...
Is it resolved? The green button at the top is great!

Let him who has never opened a user manual throw the first mouse ;-)

Hello
Your video card does not support both HDMI ports, so if you have another video output (SVGA, DP) on the computer, you can try with another cable or an adapter.
Does your tablet only have HDMI?
Cheers
--
If the answer helped you, a little thank you is very nice...
Is it resolved? The green button at the top is great!

Let he who has never opened a user manual throw the first mouse ;-)

Hello
I think it's worth testing, a DP cable isn't too expensive.
Moreover, you'll be getting the optimum quality for the main screen, as DP has superior qualities to HDMI, though it may not be noticeable, it all depends on your screen ;-)
You connect the main screen via DP and the tablet via HDMI.
See you later
--
If my answer helped you, a little thank you is really nice...
Is it resolved? The green button at the top, that's great!

Let him who has never opened a user manual throw the first mouse ;-)

Thank you very much for paying attention to my question. My tablet is connected via a USB cable and an HDMI cable (USB adapter), and I am connected to my main screen via HDMI (I should mention that I had a similar setup on my old PC and everything worked). I built my PC myself and I am running Windows 10.

Indeed, the tablet displays the image well when it is alone via HDMI, what should I do?

Hello again,
to summarize, my graphics tablet has only HDMI, my PC has an HDMI port and a DP, and my main screen has an HDMI and DP port. So I need to buy a DP cable?

Thank you very much for your help Macintosh
I will try this and keep my fingers crossed that it works