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I am making a custom cable from a VPX backplane to a DVI-I connector, and need to know if the DVI cable will work OK with a standard monitor if I do not wire up the hot plug detect pin. I will never be connecting a monitor to this cable when either the monitor or the VPX is powered up.

ocrdu
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Liz Morrissey
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  • I am coming off of a row of pins on the VPX backplane. The rest of the pins on that row are designated as ethernet pins, and are going to an ethernet connector. In order to pick up the DVI HPD pin, I would have to split it out of the VPX wafer separately. If I can operate a monitor successfully without using the HPD pin, it would make the cabling simpler – Liz Morrissey Oct 04 '21 at 14:38
  • @Hearth The HPD pin is definitely not connected to shield or something. – Justme Oct 04 '21 at 16:48

1 Answers1

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The hot plug detect pin is an output from the monitor.

You can freely ignore the pin, the monitor does not care.

However then you can't know when a monitor is connected or powered up and you can't know when it is a good time to read what video formats the monitor supports. Which basically means you can run into compatibility issues.

Just as a warning, a DVI-I connector can contain either an analog interface (DVI-A) or a digital interface (DVI-D) or both, so the monitor can use the hot plug pin to notify the PC which interface the monitor is currently selected to use.

Very old monitors simply connect a 1k resistor between DVI 5V input and HPD pins.

Justme
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