DVI   -   Digital Visual Interface

See:   HDMI    HDCP   AACS    EDID

See: EDID Information

DVI Specification

DVI is an open industry specification, which enables high-performance and robust interfacing solutions for high-resolution digital displays. DVI replaces analog technology such as VGA. The specification was introduced by the Digital Display Working Group (DDWG) as DVI 1.0 in April 1999.

Designed to transfer uncompressed real-time digital video, DVI supports PC graphics resolutions beyond 1600x1200 and HDTV resolutions, including 720p, 1080i, and 1080p.

Data is transmitted by the transition minimized differential signaling (TMDS) protocol. The DVI specification calls for at least one TMDS link which includes three data channels (RGB) and one clock control channel. Channel 0, 1 and 2 are used for video and audio data. Channels 3 is used for clock data.

DVI Specification 1.0: a single TMDS link may operate at up to 165MHz that offers 1.65Gbps of bandwidth.

This bandwidth corresponds to 165 Million pixels with 24bit color depth per second > UXGA resolution of 1600x1200 with 60Hz refresh tare and CTR blanking. Dual Link DVI has a maximum bandwidth of 2 x 165 MHz = 330 MHz, 3.30Gbps.

The maximum cable length for DVI copper cables for 1600x1200@60Hz is only one meter and for 1024x768@60Hz 9 meters, depending on the cable quality. For longer cable runs fiber optics interfaces must be used.

Single Link and Dual Link:
> Single Link DVI supports a maximum bandwidth of 165 MHz (1920x1080 at 60 Hz, 1280x1024 at 85Hz), 1.65Gbps (per TMDS !)
> Dual Link DVI supports 2x165 MHz (2048x1536 at 60 Hz, 1920x1080 at 85 Hz), Bandwidth is twice as on Single Link.

There are two DVI connection versions too, Single Link and Dual Link:
The Single Link connector has 18 pins, the Dual Link connector has 24 pins. To obtain the highest-possible resolution from DVI technology, a dual-link connection is required.

DVI Types:

  DVI-I (digital and analog) DVI-D (digital only)

DVI Type Signal Type Number of Pins
DVI-D digital only  - 24 pins (3 rows of 8 pins) 24 pins
DVI-I digital and analog  - 24 pins plus 5 (for analog RGBHV) 24 pins plus 5 for analog (RGBHV)
Dual Link dual link DVI supports 2x165 MHz (2048x1536 at 60 Hz, 1920x1080 at 85 Hz) 24 pins
Single Link single link DVI supports a maximum bandwidth of 165 MHz (1920x1080 at 60 Hz, 1280x1024 at 85Hz) 24 pins

Pins C1 to C5 carry the analog signal.

DVI Pinout

24+5-pin DVI-I connector (digital and analog - computer side):

Pin Description
1 TMDS Data2-
2 TMDS Data2+
3 TMDS Data2 Shield
4 No Connection
5 No Connection
6 DDC Clock
7 DDC Data
8 Analog Vertical Sync
9 TMDS Data1-
10 TMDS Data2+
11 TMDS Data1 Shield
12 No Connection
13 No Connection
14 +5 V Power
15 Ground (for +5 V)
16 Hot Plug Detect
17 TMDS Data0-
18 TMDSData0+
19 TMDS Data0Shield
20 No Connection
21 No Connection
22 TMDS Clock Shield
23 TMDS Clock +
24 TMDS Clock -
C1 Analog Red
C2 Analog Green
C3 Analog Blue
C4 Analog Horizontal Sync
C5 Analog Ground (analog R, G & B return)

Interconnectability of DVI and HDMI

DVI and HDMI signals are basically compatible. DVI will carry all HDMI signal components that are covered by the DVI standard and HDMI will carry all DVI signal components that are covered by the HDMI standard. Most significant difference: HDMI carries audio channels and all the new features of HDMI 1.4 are not covered by DVI.

HDMI > DVI and DVI > HDMI adapter


With DVI, HDCP (high definition content protection) was introduced by the entertainment industry. It is a "key" encoded into the DVI signal that prevents video data piracy.
If a source is HDCP coded and connected via DVI without the proper HDCP decoding, the picture is put into a "snow vision" mode or changed to a low resolution. For normal content distribution the source and the display device must be enabled for HDCP "software key" decoding.


DVI-Cable Length

For transmission of DVI signals over longer distances than 5 meters, especially over 20m, the use of glas fiber is the only solution. Cables from Opticis (www.opticis.com), Gefen (www.gefen.com) and others: