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jsmithrFlag for United States of America

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What type of DVI to VGA Cable should I purchase?

HP LaptopI have an HP EliteBook 8560w and an HP 230W Docking Station.

Docking Station Link

I have two Samsung 24" Monitors.

I would like to Dock the Laptop in the Docking Station and benefit from the Dual Monitor Setup.

Here is where things get tricky:

I already have a workstation in place that uses the DVI Inputs on the two Samsung Monitors for its video signal. To make matters worse, the Docking station for the HP Laptop has 1 DVI and 1 VGA output.

So, what I need to accomplish is the following:

Laptop > Docking Station > 1 VGA Out | 1 DVI Out >  Monitor's VGA In | Monitor's VGA In

I ordered a DVI to VGA Cable from Amazon, but it didnt fit in the DVI Port on the back of Docking Station. I did a little more digging and I think it was because the DVI Connection on the Cable was a DVI-A, but the docking station port was a DVI-D [not sure about that].

I am not a hardware person so I need a little assistance identifying and understanding DVI Technology, the hardware on my laptop and how the signal should be properly routed through the docking station to the Samsung monitors.

I think I need to know the following:
1. Does my laptop send an analogue signal through the DVI output, or is it only digital?
2. Is there a cable [compatible with my laptop] that will successfully convert the DVI signal to VGA?
3. Will I lose the maximum supported resolution of the laptop by using the VGA Outputs?

Anyway, hope all this makes sense. Let me know if you have any additional questions.
Note: I am aware that I could just simplu unplug on DVI cable and use that input when I want to use the docked laptop -- I am lazy. I also know that I could invest in a KVM Switch, but some of the ones I priced were around $300 beans which is a little out of my price range.

Jason
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Darr247
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A couple of questions ...

=>  First, are you sure the laptop supports BOTH of the outputs on the docking station at the same time and with different outputs?     Try this  (unplug one display from your workstation so you can do this test):    (a)  Connect the DVI output to one of your monitors;  (b)  Connect the VGA output to the other monitor;  and (c)  Now see what configurations the laptop supports.   Not all laptops will support two independent external displays in addition to the internal display -- and some won't even support two external displays with the internal display off.

=>  Now that you're certain what configurations the laptop supports, you'll know if you can do what you want.      If you can only support one external display, you don't have a problem -- just use the VGA output on the docking station.    If you CAN support both external displays, then the simplest approach is to use a VGA output for one of the outputs from your workstation -- assuming that the workstation has a DVI-I output.     If the workstation is also just DVI-D, then your only option with your current hardware is to use a DVI-D to VGA converter, such as the StarTech noted above by Darr247.  [Newegg sells the same unit at the same price as Amazon: http://www.newegg.com/Product/Product.aspx?Item=N82E16815158189 ]
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@Darr247Posted ,

The specs for the Docking Station state it has: 1 DVI-D.
Here is a picture of the port. It does not have the 4 alalogue pins surrounding the flat pin on the right. Does that impact the purchase of the item you recommend from NewEgg?

User generated image
@garycase,
I know that the laptop / docking station supports dural monitor output just so long as the laptop lid is closed because we have the same laptop, docking station and dual monitor setup at work.

So, correct me if I am wrong, but it looks like since the docking station port does not have those 4 pins surrounding the flat pin, I will need to spend the $109 on the startech converter?

Thanks for all of your help,
Jason
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As I mentioned above, don't forget to check your workstation outputs.    If they're DVI-I, then you can simply use a DVI-I to VGA cable for the workstation, and use the DVI input on one of the displays for the docking station.    That will save you the cost of the converter.
Hah. That *does* sound like the simplest way.  But until you explained it again, I did not grok that from "If you CAN support both external displays, then the simplest approach is to use a VGA output for one of the outputs from your workstation -- assuming that the workstation has a DVI-I output" either.  :-)
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Yep, it didnt get it until @garycase explained it again, either. I gave it a shot and this was the result:

I could get a VGA signal from the DVI Port on the workstation to one of the monitors, BUT, it was not a crisp image. The best way I could describe it is that the rendered image on the monitor "wiggled" and was blurry.

I am going to try a different VGA cable as soon as I find one.

Jason
You should not see obvious degradation of the image with a VGA connection at that resolution.    "Wiggly & blurry"  tends to indicate a poor bandwidth in the connection -- either a bad adapter or a bad cable.

For the best possible bandwidth, a direct cable eliminates the need for an adapter -- resulting in only 2 connection points instead of 4 (every connection point causes some signal degradation):

http://www.monoprice.com/products/product.asp?c_id=102&cp_id=10209&cs_id=1020905&p_id=5911&seq=1&format=1#largeimage
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@garycase,

That is the exact cable I originally purchased from Amazon [that I intended to use with the Docking Station].

I will try using that cable attached to my workstation this evening and report back with the results.

Jason