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The 2009 Hyundai Genesis has a combo CD player / stereo / Navigation / car information system. It has an LCD panel that displays information from this system but I'd like to get it working with a different display.

I found a pinout for the connector (see below - top row), and it has Tx0-/+, Tx1-/+, Tx2-/+, TxCLK-/+.... and then one labeled GND and one labeled Data.

2009 Genesis Stereo Nav Pinout

With three TX pairs and a TxClk pair this sure looks like HDMI to me.

And I tested the one labeled GND and it is, in fact, connected to the metal casing for the unit. But what about the one just labeled data?

I watched HDMI 2.1 & TMDS Crash Course and while this is a proprietary connection I think it's possible that the additional wire would be one that is part of the HDMI spec. According to the video, the TX0,1,2 and CLK pins are required but an HDMI cable could have some optional ones including DDC/I2C, HEC (ethernet), ARC (audio return), or CEC/hotplug ( see diagram from video below).

There's no reason for this to have Ethernet or Audio Return. I think I2C needs two wires, not "one wire and a ground". And there isn't a 5V source in the cable so I don't see how it could be the hotplug detect wire. I'm stumped.

What would the Pin #5 "Data" wire be?

HDMI Cable Wires Pinout

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2 Answers 2

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It's highly unlikely to be HDMI.

Much more likely is that it is raw LVDS - which is very common with laptop displays and flat panels in general. If you know what the pixel resolution of the display is, you could try an HDMI/DVI/VGA to LVDS converter as you might use for converting a laptop panel.

While it is possible that it could be something like eDisplayPort, I doubt it.

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  • \$\begingroup\$ Car displays often use non-consumer interfaces. My Toyota used Gigabit Video Interface (GVIF) developed by Sony. \$\endgroup\$ Commented Apr 10, 2021 at 1:54
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To answer your only question : Every wire in HDMI except CEC is needed to pass picture.

If that connector even uses HDMI protocol, there is not enough pins to build a HDMI adapter, it needs to be more complex than just a cable.

There is a good chance that is not even HDMI. It could match DisplayPort as well. Most likely it is just LVDS. Or some other.

The other difficulty is how would you know what to talk on the data line to have a picture out from the connector.

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  • \$\begingroup\$ So, to clarify, you're saying of the 19 wires in an HDMI connector if 18 of them are not connected then it won't work? I don't think that's accurate. \$\endgroup\$
    – cwd
    Commented Apr 9, 2021 at 23:36
  • \$\begingroup\$ Why you don't think it's accurate? So didn't the crash course video explain what each wire does and why each wire is important? \$\endgroup\$
    – Justme
    Commented Apr 9, 2021 at 23:54

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