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Azarien wrote on 2022-12-05, 12:42:

I have a Samsung SyncMaster 551s but I need an extension cable (about 1.5 m) to use it with my setup. The problem is that all ED […]
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I have a Samsung SyncMaster 551s but I need an extension cable (about 1.5 m) to use it with my setup. The problem is that all EDID information seems to be gone if I use that extension cable.
The monitor is recognized as a non-PnP, I can still set various resolutions in Windows 10 but some are missing and only 60 Hz works.

Forcing a PnP monitor or a specific one (SyncMaster 550s being the closest available choice) doesn't work - there's no error but it stays as non-PnP.

Tried on a laptop with VGA output, same thing happens.
Is this a known problem with VGA extension cords? If I hunt for a better cable what should I look for?

Standard extension cables may not use all the pins needed for VESA DDC communication with your monitor.
https://blogs.uoregon.edu/projectiondesignpdw … uts-16fe4wk.png
https://www.pcreview.co.uk/threads/what-is-pi … -cable.4016582/

Falcosoft wrote on 2022-12-05, 15:26:

Standard extension cables may not use all the pins needed for VESA DDC communication with your monitor.

I checked the cable and it seems that pins 9, 11, 12 and 15 have no connection. This is quite bad. The cable is half-useless this way. And there's no way of telling if the cable is a good one without actually checking if it works properly...

Azarien wrote on 2022-12-07, 06:57:

Falcosoft wrote on 2022-12-05, 15:26:

Standard extension cables may not use all the pins needed for VESA DDC communication with your monitor.

I checked the cable and it seems that pins 9, 11, 12 and 15 have no connection. This is quite bad. The cable is half-useless this way. And there's no way of telling if the cable is a good one without actually checking if it works properly...

Maybe you should search for cables where "DDC compatibility" is explicitly mentioned.
https://www.tvcables.co.uk/vga-extension-cable-5m.html