What is DVI?
DVI (Digital Visual Interface) is a video connection designed to replace analog VGA with a digital signal from the graphics card to the monitor. It uses a large rectangular connector with up to 24 pins in three rows plus a flat blade, held in place with thumbscrews. DVI carries video only; the standard has no audio. HDMI and DisplayPort have largely replaced it, but it's still common on older monitors, projectors and graphics cards.
DVI-D, DVI-A and DVI-I
| Type | Signals | How to spot it |
|---|---|---|
| DVI-D | Digital only | Flat blade with no pins around it |
| DVI-A | Analog only (the same signal as VGA) | Blade with four pins around it and fewer pins in the main grid |
| DVI-I | Digital and analog | Main pin grid plus the blade with four analog pins around it |
DVI-D and DVI-I also come in single-link and dual-link versions. Single-link handles up to about 1920x1200 at 60 Hz; dual-link adds a second set of data channels for resolutions such as 2560x1600 at 60 Hz.
DVI and other connectors
- DVI to HDMI: DVI-D uses the same digital video signaling (TMDS) as HDMI, so a passive adapter or cable works for video. You still won't get audio from a standard DVI port, and protected content only plays if both ends support HDCP.
- DVI to VGA: a simple passive adapter works only on a DVI-I or DVI-A port, because those carry analog signals. A DVI-D port has no analog output, so connecting it to VGA takes an active converter.
- Fit: a DVI-D plug fits a DVI-I socket, but a DVI-I plug won't fit a DVI-D socket because of its four analog pins.
Some graphics cards can send audio out of their DVI port through a matching HDMI adapter, but that's a vendor addition, not part of DVI.
Troubleshooting DVI connections
- No sound: expected with DVI. Use a separate audio cable or move to HDMI or DisplayPort.
- No picture or flickering: reseat the plug, tighten the thumbscrews and check for bent pins.
- Resolution capped below native: a single-link cable, port or adapter on a dual-link monitor.
- No signal through a VGA adapter: the port is DVI-D, which has no analog output.
For the CompTIA A+ exam
Core 1 (220-1201) objective 3.2 lists DVI among video cables, alongside HDMI, DisplayPort, VGA and USB-C, and objective 5.3 covers display symptoms such as audio issues and physical cabling problems. Know the three variants (DVI-D digital, DVI-A analog, DVI-I both) and that DVI carries no audio, while HDMI does.