What Is DVI?

DVI, the Digital Visual Interface, is a video connection standard published by the Digital Display Working Group (DDWG) in 1999. It was designed to send video digitally from a computer to a flat-panel monitor, instead of converting it to analogue VGA and back again, which gave sharper text and a stable picture at the native resolution of LCD panels.

DVI uses the same TMDS signalling that HDMI later adopted, which is why the two convert with a passive adapter. It was the standard digital monitor connection through the 2000s and is still fitted to many industrial computers, capture cards and monitors, where its screw-locked connector and long service life are valued. Graphics cards and consumer monitors have mostly dropped it in favour of HDMI and DisplayPort, so new DVI equipment is now largely industrial.

DVI connectors share the same outline but differ in which pins are fitted. The flat blade on one side, with or without four pins around it, tells you whether analogue video is present.

A DVI-D plug fits a DVI-I socket, but a DVI-I plug will not fit a DVI-D socket because of the extra analogue pins. If in doubt, a DVI-D cable is the safe choice for digital monitors.

A single DVI link has three data channels running at up to 165 MHz, enough for 1920 × 1200 at 60 Hz with reduced blanking. Dual-link DVI adds a second set of three channels on the middle pins, doubling the bandwidth to reach 2560 × 1600 at 60 Hz, or higher refresh rates at full HD.

Dual link only helps when the graphics output, the cable and the monitor all support it. For the 1024 × 768 to 1920 × 1080 panels used on most industrial monitors, single link is enough. Dual link mainly matters for large high-resolution medical and design displays, and for older 120 Hz monitors.

DVI sits between VGA and HDMI, and its relationship with each explains most of the adapters you will see.

Match the cable to the connectors at both ends and to the resolution. For a digital monitor, a DVI-D cable is the usual choice; use DVI-I only where one end needs the analogue signals, and DVI-A only on analogue equipment. Single-link cables have a gap in the middle of the pin block, while dual-link cables are fully populated. A dual-link cable works on single-link equipment, but not the other way round.

The DVI standard sets no maximum length. Standard copper cables are typically reliable to around 5 m at 1920 × 1200, further at lower resolutions, and active or fibre DVI cables extend that to tens of metres. Good shielding and the screw locks matter more on a factory floor than in an office, because nearby drives and motors add electrical noise.

DVI remains common in industrial equipment for the same reasons it has lasted: the screws keep the connector seated on a vibrating machine, and long-life designs keep the same interfaces for many years. Many of our embedded box PCs still have a DVI-D or DVI-I output alongside HDMI and DisplayPort, and some of our industrial monitors keep a DVI input for older computers.

On the capture side, DVI-I is a practical input because one socket takes DVI and, through an adapter, VGA or HDMI sources. Our DVI capture cards include PCIe and mini PCIe cards and a USB device, several of which accept DVI, HDMI and VGA on the same input. They suit medical imaging, simulators and legacy machine outputs that need to be recorded or analysed.

We fit the DVI, HDMI or VGA outputs, adapters and capture cards that match your monitors and sources as standard, and test each connection before the system ships.