Instruction: Answer the given question by extracting information from the supporting document.

Input:
Question: Why is this 18-pin? My monitor's DVI port is 24-pin.
Document: The DVI cable works great. I bought a new 24" 1080p monitor. It has a VGA and DVI port. I hooked the monitor up to my Mac with VGA and it refused to display in 1080p, so I bought this cable and it worked as expected. I was wanting a cheap cable that would do the job and this one worked great!
I am new to the DVI standard but this cable fit my new display card and dvi port on my monitor and works great.
Have a dual port video card (1 port VGA and 1 port DVI) so I needed this cable to connect my 2nd monitor so I could run dual screens.
Cheap and worked great for my DVI monitor. Be caseful when buying these types of cables --- there are many similar choices. This one was perfect for connecting my HP DVI monitor to my HP computer's DVI graphics card port.
Works perfectly.The cable came brand new, had twist-ties on it, and had plastic protective covers covering the pin connectors.When I ordered this, I was wondering what a DVI-M cable was, but on the actual package it says DVI/M to DVI/M which I guess stands for DVI Male to DVI Male.The cable is actually a DVI-D (Dual Link)
Bought three of these to hook my three 24&#34; monitors up to my radeon 7970, works as advertised and for the money you really can't beat it!
Without this cable, Windows 8 could not properly recognize or utilize my 24&#34; widescreen LCD monitor. It registered it as a generic non-plug-n-play CRT.
I bought these to give me a little extra distance on my third monitor. They work wonderfully. I run three 24" monitors and have them sli in span mode. Span mode requires nice cables and will complain if you have lesser cables. It did not complain about this at all! Thanks!
I have 3 of these cables currently in daily use on monitors from 17&#34; 4:3 at 1280x1024 to 24&#34; at full 1920x1080 (1080p). They are high quality, plenty of length for most applications, and have exhibited no quality or signal issues. I can't say anything bad about them. Highly recommend for any application.
The cable is not a legitimate Dell cable, and was incapable of displaying my monitor's highest resolution. Possibly a good fit for low end purposes, but be aware you're buying a knock off.
Answer: A DVI-D connector on a graphics card sends out a digital signal only, while a DVI-I connector, which carries both an analog and digital signal, can send out a digital signal (for digital displays such as flat panel LCD monitors) as well as analog signal (for older displays such as a CRT monitor) using a DVI to VGA adaptor.  DVI-I connectors contains more pins than the DVI-D connector.  The extra pins on a DVI-I connector carry the analog signal which the DVI-D connector does not have. If you only plan to use a LCD or such type of screen either cable will work. MOSTLY all screens support full DVI-I/D connections for easy compatibility. You just can't plug a DVI-I cable into a DVI-D slot. The four extra pins would get crushed. Good view of ports http://cdn.overclock.net/4/47/500x1000px-LL-4715188d_13611i85823D50731521FC.gifAbout DVI-D Dual and Single Link:So what does dual link actually mean?  "Dual Link" DVI use two TMDS digital signal transmitters and 8 wires to send data, while "single link" uses one TMDS digital signal transmitter and 4 wires. The Dual link DVI effectively doubles the power of transmission and provides an increase of refresh rates and signal quality.  Specifically a DVI single link 60-Hz LCD can display a resolution of 1920 x 1200, while a DVI dual link 60-Hz LCD can display a resolution of 2560 x 1600.If you look at the plug-ends of a single "dual link" cable, you see it actually has more pins packed in than standard single link DVI cables (18 vs 24 pins). In this case, more pins and wires in the cable translates to more bandwidth. Where this becomes slightly confusing is that on most of the current FireGL accelerators you will see two Dual Link DVI outputs. This means you can drive two high resolutions monitors, each up to 2560 x 1600.