Extending DisplayPort 20m

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chevrolux

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#271794 27-May-2020 09:40

So have a weird requirement (in a commercial setting), to get a DisplayPort link running over around 20m - we don't normally get involved with this stuff.

Here is what i got:

This HDMI cable:
https://www.pbtech.co.nz/product/CABUNI1030/Unitek-Y-C1030BK-20m-UltraPro-HDMI-20-Fibre-Active

These adapters:
https://www.pbtech.co.nz/product/CABSTT3493573/StarTech-DP2HD4K60S-DisplayPort-to-HDMI-Adapter

The guts of it is, we can get an image displaying when there is just one DP-HDMI adapter on the PC end, and HDMI input on the monitor. However, when using the proper monitor with DP input (and adding the second adapter in), there is no image.

The whole thing here, is the DP requirement is only going to be for a year or so until the PC gets upgraded and then they can just use the plain HDMI cable. I always though DP to HDMI was purely a wiring/connector change, but clearly I was wrong.

How do we tackle this?

trig42

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#2492549 27-May-2020 09:48

I was pretty certain it was just a plug difference for video between HDMI and DP.

It could be that adding the adapter at the end is the straw that breaks the camels back when you consider the other adapter and the 20m cable.

You could try HDMI over CAT-6 baluns - they are designed to go good distances. One here (must be other options around too) https://www.pbtech.co.nz/product/AVESTT4478080/StarTech-HDMI-over-CAT6-Extender-Kit---4K-60Hz---H

chevrolux

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#2492557 27-May-2020 09:52

Yea the issue is still the DP connectors on each end though. We would still need to adapt the HDMI inputs on the baluns to DP.

I don't think the HDMI cable length is the issue as it's an active fibre optic cable, not just a plain 20m HDMI cable. I'm guessing there is some circuitry in the DP-HDMI adapters.

cyril7

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#2492647 27-May-2020 11:00

Hi, HDMI and DP are two totally different signalling technologies, and while you can use a simple wire adaption as is commonly done, I think you will find the wheels will fall off if you add an active HDMI link in the middle that is incapable of dealing wtih LVDS (as opposed to TDMS) or the fact that DP uses packetised traffic, where HDMI does not.

Cyril

chevrolux

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#2492764 27-May-2020 13:37

Thanks @cyril7 - that was my lack of understanding sorted out.

Manage to get a hardware upgrade happening for the monitors... so it's going to be a non-issue soon. Considering the machine is a few million dollars worth, $1000 worth of monitors is not such a big deal it turns out!