DVI Tutorial - Digital Visual Interface Tutorial - PacificCable.com

The following information is used by permission from the Wikipedia under the GNU Free Documentation License.

The Digital Visual Interface (DVI) is a video connector designed to maximize the visual quality of digital display devices such as flat panel LCD computer displays and digital projectors. It was developed by an industry consortium, the Digital Display Working Group (DDWG).

The DVI connector usually contains pins to pass the DVI-native digital video signals. In the case of dual-link systems, additional pins are provided for the second set of data signals.

The DVI connector may also incorporate pins to pass through the legacy analog signals using the VGA standard. This feature was included in order to make DVI universal, as it allows either type of monitor (analog or digital) to be operated from the same connector.

The connector also includes provision for a second data link for high resolution displays, though many devices do not implement this. In those that do, the connector is sometimes referred to as DVI-DL (dual link).

The DVI connector on a device is therefore given one of three names, depending on which signals it implements:

DVI-A (analog only)
DVI-A Male

DVI-A Female

DVI-I (digital and analog)
DVI-I Male Single-Link

DVI-I Female Single-Link

DVI-I Male Dual-Link

DVI-I Female Dual-Link

DVI-D (digital only)

DVI-D Male Single-Link

DVI-D Female Single-Link

DVI-D Male Dual-Link

DVI-D Female Dual-Link

I need a DVI-I to DVI-D cable - What part number do I buy?
A DVI-I enables digital and analog signals. A DVI-D only allows digital signals. The part number to buy is DVIDL-length
Why are your DVI cables so much less?
You are coming right to the source. Our cables meet all wiring specifications. We don't know why everybody else is so expensive.
Is there a distance limitation?
Yes. For digital DVI cables there is a 5 Meter distance limitation. If you go longer the video results will be unpredictable and not guaranteed. The only way to safely and efficiently go longer distances is to use our OC and OLC series DVI fiber cables.
Do I need Dual-Link or Single-Link?
This depends on your equipment. Check with your equipment documentation. If you are not sure which you need then purchase the Dual-Link cables. Dual-Link cables are backwards compatible with Single-Link so they will work with both connection types.
Can I connect a DVI-A to a DVI-D?
Because DVI-A is analog only and DVI-D is digital you can not directly connect a DVI-A device to a DVI-D device.
Can I connect a DVI cable to VGA?
You can connect a DVI-I or DVI-A directly to VGA using our DVIVGA cables because DVI-I and DVI-A send analog signals. You can not directly connect a DVI-D to a VGA because DVI-D only uses digital signals. In order to connect a DVI-D to VGA you first need to use a DVI Converter to electronically convert digital to analog and analog to digital.
What is HDCP?
HDCP stands for High-bandwidth Digital Content Protection. HDCP encrypts the digital signal to prevent it from being recorded. HDCP encryption / decryption takes place within your equipment. Check your equipment documentation to see if it offers HDCP. Cables simply pass the digital signal between the HDCP compliant equipment.
What is the TFT LCD?
TFT stands for "Thin Film Transistor" and describes the control elements that actively control the individual pixels. For this reason, one speaks of so-called "active matrix TFT's". LCD means "Liquid Crystal Display" and stands for monitors that are based on liquid crystals.
What's the difference between CRTs size and TFT size?
The visible diagonal size of a CRT tub monitor is always smaller than the tube's actual diagonal size. For example: a 17-inch CRT monitor has an edge area and it's visible diagonal is only 16-inches. But TFT LCD monitors do not have an edge area. This means that a 15-inch TFT LCD monitor is almost the same as the 17-inch CRT monitor.
What's the Contrast Ratio?
The Contrast Ratio is derived from the maximum and the minimum values for brightness.

What's the difference netween Digital and Analog Interface? Any advantages or disadvantages?
TFT LCD monitors with an analog VGA interface dominate the market. Because it is easy to install PC basis and not purchase a new graphics board. Although digital TFT LCD monitors don't need to adjust clock and phase and the no signal losses advantage. The Digital Interface standard has totally different connectors and it is not easy to buy a suitable graphic board. So the analog TFT LCD monitors still dominate the market. The following table gived you an overview of the most important points:

Digital Control	Analog Control
Advantages No signal losses due to DA and AD conversion Geometry, clock and phase settings unnecessary - therefore simple to use Lower costs as less electronic circuitry required Disadvantages Currently three standards (P & D (M1DA), DFP, and DVI) Low availability of models with digital interfaces Requires graphic board with digital output	Advantages Compatible with standard VGA boards on a broad installed PC basis Not necessary to purchase separate board Disadvantages Clock and phase of the TFTs must be synchronized with the analog signal to avoid pixel jitter, which is a relatively complex issue Cables sensitive to external influences High cost of signal conversion inside the display Upgrade to digital interface not possible

Digital Control

Analog Control

Advantages

No signal losses due to DA and AD conversion
Geometry, clock and phase settings unnecessary - therefore simple to use
Lower costs as less electronic circuitry required

Disadvantages

Currently three standards (P & D (M1DA), DFP, and DVI)
Low availability of models with digital interfaces
Requires graphic board with digital output

Advantages

Compatible with standard VGA boards on a broad installed PC basis
Not necessary to purchase separate board

Disadvantages

Clock and phase of the TFTs must be synchronized with the analog signal to avoid pixel jitter, which is a relatively complex issue
Cables sensitive to external influences
High cost of signal conversion inside the display
Upgrade to digital interface not possible

How many Digital Interfaces are there now? Which one do I choose?
Currently there are three digital interface standards (P & D (M1DA), DFP, and DVI) in the market. The following table is the comparison and summary of the three interface standards. According to the table, DVI will be a standard in the future. DVI not only allows high resolutions, it also enables the connection of analog devices.

Standard	P & D (M1DA)	DFP	DVI
Owner	VESA (Video Electronics Standards Organization)	DFP Group (Digital Flat Panel Group) and later VESA	DDWG (Digital Display Working Group)
Revision / Date	1.0 / Jun 06, 1997	1.0 / Feb 14, 1999	1.0 / Apr 02, 1999
Web page	www.vesa.org	www.dfp-group.org	www.ddwg.org
Workgroup leader	VESA	Compaq	Intel
Compatibility	Own standard	P & D (M1DA) compatible (adapter possible)	P & D (M1DA) and DFP compatible (adapter possible)
Transfer protocol	TMDS - Transmission Minimizing Differential Signaling (PanelLink)	TMDS (PanelLink)	TMDS (PanelLink)
Max. Pixel rate (Dot Clock)	165 MHz x 1	165 MHz x 1	165 MHz x 1
Max. number of channels	3 channels (single link)	3 channels (single link)	6 channels (dual link)
Color depths	12 or 24 bit	12 or 24 bit	12 or 24 bit
Max. Resolution	SXGA (1280 x 1024)	SXGA (1280 x 1024)	(Single Link) WUXGA 1920 x 1200 @ 60 Hz (Dual Link) WQXGA (2560 x 1600) @ 60 Hz
Optional transfer of other signals possible using the same connector	Analog VESA video, USB, IEEE 1394-1995	No, only digital video	Analog VESA video
Digital Connector	P & D (M1DA)-D (30 pin)	MDR20 (20 pin)	DVI-D (24 pin)
Analog/Digital combination connector	P & D (M1DA)-a/d (30+4 pin)	No	DVI-I (24 + 4 pin)
Connector width	40.6 mm	33.4 mm	37.0 mm

DVI Wire Specs

DVIISL Wire Specs