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I am going to buy BenQ G2220HD 22" LCD display.

I already have an XFX GeForce 9400GT.

Both support DVI. But the confusion came when I wanted to actually buy a DVI cable.

I got confused with DVI, DVI-D and DVI-I and then Single link and Dual link!

Can someone tell me whether this cable can be used to connect my 9400GT to my BenQ display? If not, what kind of DVI cable should I buy - DVI, DVI-D, single link, dual link, DVI-I??

Basically, GeForce website says the card's output is Dual Link DVI. The BenQ website says the monitor takes input as DVI-D. What are my options now? What kind of DVI cable should I get? Please don't suggest brands because from experience I know that most of them won't be available here in India. Can you please just tell me the TYPE of DVI cable I can use?

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2 Answers 2

up vote 4 down vote accepted

DVI-D is what most monitors take - it is the pure digital signal.

DVI-A is just the analogue signals, as would be found on VGA' d-stub connector. This is rarely seen.

DVI-I carries both the digital and analogue signals. This is what most video cards output, so you can either connect the output port directly to a DVI-D or DVI-I port on a monitor or through an adaptor to a VGA port on a monitor that has no DVI input. Monitors that expect DVI-D will accept a DVI-I cable - they'll just ignore the signals on the extra pins.

Single-link DVI has enough signalling bandwidth to support a 1920*1200 display at 60Hz so usually isn't required for home arrangements with LCD screens (60Hz is usually fine for LCD displays, unlike CRTs, and displays with resolutions above 1920*1200 are unlikely to be found outside specialist areas). Most modern graphics cards support dual-link though, in case you want to run at a resolution and refresh rate that requires it. As with DVI-D/DVI-I, the extra pins for dual-link output should simply be ignored if present but the monitor does not need/support them.

Edit: so in summary, that monitor+card+cable should work fine together. See http://en.wikipedia.org/wiki/DVI-D#Connector for more detail.

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A single link cable can be used to connect devices that are capable of delivering dual link data - only some of the data will not flow through but its enough to run 1920*1200. Is that right? –  delete my account Jun 15 '10 at 10:56
    
Yes, both devices will see the missing pins as meaning they are talking to a single-link device, and will limit their capabilities accordingly (only sending/expecting data down the one set of lines and refusing to move to a mode that would require the extra bandwidth). –  David Spillett Jun 15 '10 at 11:08
    
These days, DVI-A is mostly used for cables that have a VGA connector at one end and a DVI connector at the other. Cables of this type are quite useful for laptops and (occasionally) plugging old monitors into machines without a VGA port. –  ConcernedOfTunbridgeWells Jun 15 '10 at 11:51

Video cards today output both analog and digital signal in the DVI connector thus you can use any type of cable that is suitable for your monitor. Usually monitors with a DVI connector will take the digital signal (DVI-D), while those taking analog signal are likely to use a D-sub (AKA VGA) connector.

I have two monitors, Benq G2220HDA 21.5" and Philips 170S 17". Both accept analog signals, however, I use DVI-I dual link cables exclusively, since this allows me to replace the monitor without hunting for a cable. I simply use a cheap DVI -> VGA converter at the back of the monitor.

Here is a picture of the various DVI connectors. The second from the top (DVI-I dual link) is what the video cards have on the back and will work with any cable. You should get a cable with that connector, as it will work with any monitor, be it digital or analog, single or double link.

Image of DVI connectors

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