Connection to RJ45 wall socket

I don't like that ...
Why does it always show non-parallel the thing?
Don't you have other cords?
You're missing the 1 on your yellow cable; there must be a bad contact on it.
Can you check the other sockets with your little flat cables?
And compare with the one that works.
I don't really understand the logic of the battery indicators either.

Hello,

Thank you for your feedback.
I managed to connect my PC in my living room by following your diagram...

However, upstairs, it doesn't work in any of the bedrooms, despite my checks on the good condition of the connections. (All the cables are well connected with the correct colors of the 8 small cables in the right places...)

I don't understand why the network isn't working upstairs...

Do you have any ideas?

Thanks in advance.

Did you take apart the sockets?
I assume your jacks are not labeled, so you’re trying them all one by one...
You can already put back the one that works.
If you don’t see anything visually, you’ll need to invest in a wiring tester.
On the ADSL side, you can remove the T-connector adapter and plug the RJ11 directly into the modem socket of the master filter.

For the tester, I can help you, no problem.
The master filter is where the ADSL from your box is connected to the right of the DTI.
The adapter is the two black T-shaped sockets placed end to end, you should be able to plug the RJ11 ADSL cable directly in its place.

I don't know this one, we'll find out, but it should work if the battery is good and the device is too.
I would like to know how it distinguishes the pairs.
Do you have two parts or just one?
Here, that's good, we have some documentation:
https://www.velleman.eu/downloads/1/vtlan7a701.pdf
So
1/ test 2 RJ45 cables directly at both ends.
2/ test the sockets by connecting each part of the tester with the two tested cables to the cable being tested.
3/ see the results.

Well, thank you,
in the first photo, we can already see that 5 and 6 don't connect at the other end.
This socket needs to be re-cabled.
In the following photos, the cores on the patch panel side look great, but on the socket side, it's a bit of a mess.
It's better to disconnect these sockets, cut 1cm of wire, and re-cable them respecting the colors in mode B.
It looks like it's not the same person who did both ends.
Otherwise, you're lucky to have real network cable and quality equipment (Legrand) at the ends.
It should work by redoing the wall sockets.
As for your tester, I understand better about the battery from your explanation regarding the photos, although it's strange to have a green light for low battery.
I still haven't understood why it shows crossed either.

Hello,

So I'm going to cut the cables, shorten them and put them back in the right places, and I'll let you know how it turns out ;)

Thanks a lot