Whats with the cables?

dirkpitt · October 19th, 2003, 11:48 PM

Hi guys,

I'm just curious with the difference between the DVI-I single link and DVI-I dual link. and also what is the difference or purpose of DVI-D Dual Link. and DVI-A.

i got the pictures from this site: http://www.si87.com/Wizards/connectors.html

thanks

orkalass · October 20th, 2003, 02:44 PM

Hey man. I think the difference is that a Dual-DVI can handle 2 monitors, and the single DVI can only handle one. i have a dual and that's the case with me. the more pins would be for outputting two images at once at DVI quality without lag or loss of color. Hope that helps bro

ilovetheusers · October 20th, 2003, 08:33 PM

http://www.tech-plus.co.uk/system/index.html

Analogue – VGA/SVGA

The standard connector for the VGA/SVGA monitor for the past 15 years has been the 15 pin High density D-Type connector. A female HD15 connector being present on both the graphics card and monitor with male HD15 connectors on the monitor cable. The first 3 pins of the connector carry the RGB signal to the 3 guns of the CRT, with other pins dealing with grounds, HZ and vertical sync and clock. The typical monitor SVGA cable contains 3 foam insulated coaxes for the RGB signal with 6 individual 24AWG copper wires for the other data. Ferrite cores are usually fitted to suppress interference.

Digital – DVI

The adoption of LCD technology in computer screens has led to the development of the DVI standard (digital video interface). Early LCD screens converted the analogue signal from the computer into a digital signal within the LCD display. Significant improvements in image quality have resulted from the now widespread availability of graphics cards with digital outputs thereby avoiding any signal loss from a conversion to analogue in the graphics card and then back to digital at the screen.

A new standard connector has been developed for the Digital Video interface comprising a rectangular block of 24 pins for the digital signal plus 4 pins either side of an earth pin for transmission of a conventional analogue signal where required.

Four different versions of this connector are used:

DVI-D single link

- 18 of the 24 pins are used to carry a digital only signal at resolutions up to 1280 x 1024. The 4 analogue pins are not present. DVI-D cables are supplied as standard with most NEC LCD screens.

DVI-D dual link
- All 24 pins are used to carry an enhanced digital signal for
High resolution LCD and Plasma screens e.g 1600 x 1280 and higher. Again no analogue pins are present.

DVI-I
This connector can support both digital and analogue signals and is used on graphics cards and monitors to provide both options without having to incorporate both DVI-D and HD15 SVGA connectors.

DVI-A
DVI-A monitor cables carrying only the analogue signal, are used where one end is to mate with a DVI-I connector and the other end with a standard HD15 connector. NEC screens fitted with only DVI-I inputs come with such a cable as standard, for connection to analogue only graphics cards.

The monitor cable itself is very different for digital signal transmission compared to analogue. The three coax cores for the RGB signal are replaced by foil shielded twisted pairs one for each colour plus a 4th twisted pair for "clock". In dual link cables two such twisted pairs are used for each colour, the graphics card driving alternate pixels down each pair to achive higher bandwith The digital signal is very delicate and effective transmission over 5 metres cannot be guaranteed, which means that analogue SVGA cables will continue to be used in many applications e.g. where display units such as plasma screens or projectors are sited over 10m, from the signal.

Choosing a DVI Cable

If both graphics card and screen are fitted with DVI-I or DVI-D connectors and the maximum screen resolution is 1280 x 1024 then a DVI-D single or dual link cable should be used with a recommended maximum length of 5m. Longer distances up to 10m may work but this cannot be guaranteed and will depend on the make of card and screen. DVI-I combined digital analogue cables should not normally be used and may well not physically fit if either device is fitted with a DVI-D connector (as it would be unable to accept the 4 analogue pins). Dual link cables are only necessary for screens with resolutions of 1600 x 1280 and higher, provided the graphics card has dual link capability.

If one device has a DVI-I connector and the other a traditional SVGA HD15 connector then use a DVI-A to HD15 cable to carry an analogue signal.

confus-ed · October 21st, 2003, 07:14 AM

... congrats ITLU ... best answer I've seen for ages ... an admirable use of cut 'n' paste !

Stalemate · October 21st, 2003, 08:57 AM

Very informative.

October 19th, 2003, 11:48 PM	#1
dirkpitt Registered User Join Date: Mar 2003 Location: somewhere far away from SARS Posts: 141	Whats with the cables? Hi guys, I'm just curious with the difference between the DVI-I single link and DVI-I dual link. and also what is the difference or purpose of DVI-D Dual Link. and DVI-A. i got the pictures from this site: http://www.si87.com/Wizards/connectors.html thanks __________________ what the heck?

October 20th, 2003, 02:44 PM	#2
orkalass Registered User Join Date: Oct 2003 Posts: 6	Whats with the cables? Hey man. I think the difference is that a Dual-DVI can handle 2 monitors, and the single DVI can only handle one. i have a dual and that's the case with me. the more pins would be for outputting two images at once at DVI quality without lag or loss of color. Hope that helps bro

October 20th, 2003, 08:33 PM	#3
ilovetheusers Flabooble! Join Date: Nov 2000 Location: Downtown Banglaboobia Posts: 6,391	http://www.tech-plus.co.uk/system/index.html Analogue – VGA/SVGA The standard connector for the VGA/SVGA monitor for the past 15 years has been the 15 pin High density D-Type connector. A female HD15 connector being present on both the graphics card and monitor with male HD15 connectors on the monitor cable. The first 3 pins of the connector carry the RGB signal to the 3 guns of the CRT, with other pins dealing with grounds, HZ and vertical sync and clock. The typical monitor SVGA cable contains 3 foam insulated coaxes for the RGB signal with 6 individual 24AWG copper wires for the other data. Ferrite cores are usually fitted to suppress interference. Digital – DVI The adoption of LCD technology in computer screens has led to the development of the DVI standard (digital video interface). Early LCD screens converted the analogue signal from the computer into a digital signal within the LCD display. Significant improvements in image quality have resulted from the now widespread availability of graphics cards with digital outputs thereby avoiding any signal loss from a conversion to analogue in the graphics card and then back to digital at the screen. A new standard connector has been developed for the Digital Video interface comprising a rectangular block of 24 pins for the digital signal plus 4 pins either side of an earth pin for transmission of a conventional analogue signal where required. Four different versions of this connector are used: DVI-D single link - 18 of the 24 pins are used to carry a digital only signal at resolutions up to 1280 x 1024. The 4 analogue pins are not present. DVI-D cables are supplied as standard with most NEC LCD screens. DVI-D dual link - All 24 pins are used to carry an enhanced digital signal for High resolution LCD and Plasma screens e.g 1600 x 1280 and higher. Again no analogue pins are present. DVI-I This connector can support both digital and analogue signals and is used on graphics cards and monitors to provide both options without having to incorporate both DVI-D and HD15 SVGA connectors. DVI-A DVI-A monitor cables carrying only the analogue signal, are used where one end is to mate with a DVI-I connector and the other end with a standard HD15 connector. NEC screens fitted with only DVI-I inputs come with such a cable as standard, for connection to analogue only graphics cards. The monitor cable itself is very different for digital signal transmission compared to analogue. The three coax cores for the RGB signal are replaced by foil shielded twisted pairs one for each colour plus a 4th twisted pair for "clock". In dual link cables two such twisted pairs are used for each colour, the graphics card driving alternate pixels down each pair to achive higher bandwith The digital signal is very delicate and effective transmission over 5 metres cannot be guaranteed, which means that analogue SVGA cables will continue to be used in many applications e.g. where display units such as plasma screens or projectors are sited over 10m, from the signal. Choosing a DVI Cable If both graphics card and screen are fitted with DVI-I or DVI-D connectors and the maximum screen resolution is 1280 x 1024 then a DVI-D single or dual link cable should be used with a recommended maximum length of 5m. Longer distances up to 10m may work but this cannot be guaranteed and will depend on the make of card and screen. DVI-I combined digital analogue cables should not normally be used and may well not physically fit if either device is fitted with a DVI-D connector (as it would be unable to accept the 4 analogue pins). Dual link cables are only necessary for screens with resolutions of 1600 x 1280 and higher, provided the graphics card has dual link capability. If one device has a DVI-I connector and the other a traditional SVGA HD15 connector then use a DVI-A to HD15 cable to carry an analogue signal. Last edited by ilovetheusers; October 20th, 2003 at 08:41 PM.

October 21st, 2003, 08:57 AM	#5
Stalemate Registered User Join Date: May 2001 Location: d4-e5 Posts: 15,085	Very informative. __________________ Human beings, who are almost unique in having the ability to learn from the experience of others, are also remarkable for their apparent disinclination to do so. *-Douglas Adams*

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October 21st, 2003, 07:14 AM	#4
confus-ed Geezer Join Date: Jul 1999 Location: In front of my PC.... Posts: 13,091	... congrats ITLU ... best answer I've seen for ages ... an admirable use of cut 'n' paste !