Which DVI Cable or Adapter Should I Use?

One of the more common questions our Technical Advisors get from customers looking to connect a DVI monitor to a computer or KVM switch, is "which cable or adapter should I use?".

Unlike other video connection interfaces (e.g VGA and DisplayPort) which typically use the same connector for each application, there are three distinct types of DVI connector that can be used: DVI-D, and DVI-I and to a much lesser extent, DVI-A. To make this even more confusing, each connector type is available in one of two styles: single-link and dual-link!

Given how rarely a DVI-A connection is used, we typically don't get a lot of questions about it - the majority of the focus is on DVI-D and DVI-I, so here's some information you might find useful about the two most common types of DVI Cable - DVI-D and DVI-I!

DVI-D ( DVI-Digital)

A DVI-D connection is fully digital. This type of connector is most likely found on a DVI monitor - it has three rows of pins and is distinguished by a horizontal bar adjacent to the pins (shown below).

DVI-D Dual-link connectors have three rows of eight pins plus the bar...

...while single-link connectors are missing the two columns of pins from the middle (two 3x3 groups of pins, plus the bar):

The extra pins in a dual-link connector enable it to support higher resolutions than a single-link connector; whereas a single-link connector is limited to 1920x1200 @ 60Hz, a dual-link connector can carry up to 2560x1600 @ 60Hz.

To convert a DVI-D signal to HDMI (digital to digital), you can use a passive adapter or cable, such as an HDMI® to DVI-D Video Cable Adapter (HDMIDVIFM) or the HDMIDVIMM6. Converting DVI-D to VGA (digital to analog) is not as easy, as it requires an active DVI Converter such as the DVI2VGACON or HDMI2VGA.

DVI-I (DVI Analog + Digital)

DVI-I connectors are usually found on video cards, KVMs, and video switches. Because this connector carries both analog and digital signals, it features rows of pins similar to those of a DVI-D connector, but also four pins around a bar or cross-shape to the side. These extra four pins are the distinguishing feature, as they carry the analog signal:

DVI-I connectors also come in dual-link (shown above) and single-link (shown below) varieties, identified the same way as for a DVI-D cable, and the resolutions supported are the same as for DVI-D. You’ll find that DVI-I sockets almost always use a dual-link connector, but it may be the case that only one link is active.

DVI-I supports nearly all other DVI formats, so the socket can accept all other DVI plugs. However, a DVI-I plug will only fit in a corresponding DVI-I socket and no other - this physical compatibility is the main reason why graphics cards provide DVI-I sockets, as they offer broader compatibility.

If you want to convert the video output from a DVI-I device, it's advisable to contact the manufacturer or consult the specifications they provide, to determine whether or not the connector produces the analog output as well. Many video cards are built with DVI-I connectors that provide only DVI-D signals, so that you can plug in any cable, and many other devices are labeled as accepting only analog or digital signals, so pay attention to any such limitations noted on specification sheets.

Here are some rules of thumb to keep in mind, when purchasing a DVI Cable or Adapter:

• Before purchasing DVI cables, find out the highest resolution your monitor accepts.  If your monitor does not accept resolutions higher than 1900x1200, there are no benefits to using a dual-link cable.
• In general, digital DVI can only be connected to/converted into other digital formats, analog DVI can only be connected to/converted to other analog formats, and DVI-I can be used for both analog and digital signals.
• You can connect a DVI-D cable to a DVI-I socket, but not the other way around.
• You can plug a single-link connector into a dual-link socket, but not the other way around.
• If your DVI-I connector provides both analog and digital signals, it can be adapted to nearly any other format by discarding the undesired signal.

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