VGA-to-DVI adapters?

[Eric Legge]

Seasonal greetings, Sysopters.

I need to know if it's possible to buy an adapter that can be used with a standard D-sub VGA monitor cable so that a video card with only a standard VGA port can be used to connect to the DVI-D port on an LCD monitor.

If there is such an adapter, does it connect to the monitor's or the video card's end of the D-sub cable?

Eric,
http://www.legge40.freeserve.co.uk/BuyerBeware.htm

[Peter M]

Not possible. DVI-D is a digital signal, you cannot convert the analog signal coming from a VGA plug to magically become digital.

[Eric Legge]

Thanks for the reply Peter M.

That's what I thought, but a friend bought an NEC DVI LCD monitor that came with a D-sub cable and what he said was an adapter that didn't fit to the monitor.

He didn't get a DVI cable with the monitor. His port on the LCD is DVI-D and the port on the video card is DVI-I.

Eric,
http://www.legge40.freeserve.co.uk/BuyerBeware.htm

[Peter M]

Now what's the question here?

DVI-D device on DVI-I graphics card output works (and fits) alright. DVI-I (I)ntegrates the (D)igital signal with an analog copy that gets used by those DVI-VGA dongles.

VGA outputs in turn do not contain a digital signal, so obviously VGA-DVI dongles - what you asked originally - are not possible.

If the monitor came with a D-sub (VGA) cable, then it is capable of using an analog signal as well.

Two ways to go: Get a DVI-D cable, or get a DVI-VGA adapter for the graphics card and use the cable you have. Most retail cards include one anyway. Image quality is better with the DVI cable, of course.

[Eric Legge]

It's an NEC Multisysnc LCD1700NX monitor, and he says that it only has a DVD-D port, and came with an adapter with a VGA cable, so this must be for use with the DVD-I port, which produces both analog and digital signals, and an analog LCD monitor.

Either the monitor has an analog port, or the vendor screwed up, not so?

Eric,
http://www.legge40.freeserve.co.uk/BuyerBeware.htm

[Eric Legge]

This bloke told me that he only has a DVI-D port on the monitor and a DVI-I port on his video card, but he was supplied with a D-sub VGA cable and an adapter.

I'm tring to figure out what the adapter was for, because it can't be one such as those listed below, because they cost as much or twice as much as the monitor.

I've just discovered an expensive solution to people who want to use a DVI-only monitor with a VGA-only video card.

The VGA to DVI Conversion Box
http://www.gefen.com/kvm/product.jsp?prod_id=1310
Cost $299.00

The VGA to DVI Adapter - http://www.gefen.com/kvm/product.jsp?prod_id=1435

The main difference of this box from the VGA to DVI Conversion Box is that it has a video scaler built in. Cost $799.00

Eric,
http://www.legge40.freeserve.co.uk/BuyerBeware.htm

[Peter M]

Originally posted by Eric Legge
It's an NEC Multisysnc LCD1700NX monitor, and he says that it only has a DVD-D port, and came with an adapter with a VGA cable, so this must be for use with the DVD-I port, which produces both analog and digital signals, and an analog LCD monitor.

Either the monitor has an analog port, or the vendor screwed up, not so?

Eric,
http://www.legge40.freeserve.co.uk/BuyerBeware.htm

Typically, these higher spec LCD screens have two inputs, one analog, and one DVI-D. Maybe your friend just hasn't found the spot where the analog cable goes? (It happens!) Yet still, he'd then need to dig out the graphics card's DVI-VGA dongle, or buy one.

The best solution is to get a DVI-D cable. Buy one or twist the screen vendor's arm to give you an appropriate cable.

Really, there's nothing left to discuss or speculate. Action time!

[Eric Legge]

Just one more thing...

He can't find a VGA input port on it, so it must be a DVI-only model.

No one in his right mind is going to spend more on an adpater than an expensive video card or monitor, so I'm wondering why those adapters exist.

Since I've been told that a DVI-I port on a video card can supply both analog and digital signals, perhaps my friend's monitor came with a simple adapter that allows a VGA cable to be used with this port and an analog input on the monitor on the dual-purpose version, and it was included by mistake.

Eric,
http://www.legge40.freeserve.co.uk/BuyerBeware.htm

[Peter M]

Well, according to Mr. D. Adams, businesses that sell stuff noone in their right minds would ever buy manage to cling on at their fingernails because there's always a considerable number of people who are not.

[Eric Legge]

I thought that the adapter that my friend got with his DVI LCD monitor had to be cheap.

He couldn't fit it to the DVI port on the monitor, but it fitted the DVI-I port on his video card, which carries analog and DVI signals.

The cables/adapters on this site cost from $39 each.

http://store.kayye.com/kayye/dviicables.html

Regards,

Eric,
http://www.legge40.freeserve.co.uk/BuyerBeware.htm

[Peter M]

Well, as I said, these adapters are meant to make a VGA port from a DVI-I _output_. DVI _inputs_ on display units most oftenly are DVI-D, so there's no analog signal to go in there - and that's also why it doesn't fit. DVI connectors are keyed so that only stuff that makes sense can be plugged together.