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Dvi To Vga Pin Assignment

DVI connectors come in three types: DVI-A (analog), DVI-D (digital) and DVI-I (integrated; analog and digital). Both DVI-I and DVI-D connectors have two distinct data rates, also known as single-link and dual-link. Each link type has a maximum allowed data rate that ensures data is not corrupted when transferred from the video card to the monitor.

DVI uses Transition Minimized Differential Signaling (TMDS) to transmit data over one twisted wire pair. A single-link DVI connector consists of four TMDS links. Three of the four links correspond to the red, green, and blue RGB video signals, while the fourth is a clock control channel. Single-link connectors operate up to 165MHz and offer 1.65Gbps of bandwidth. They support resolutions up to 1920×1200 at a refresh rate of 60Hz.

Dual-link connections double the number of RGB TMDS pairs – excluding the clock pair – through parallel connections, thus enabling 2Gbps of bandwidth. They support higher resolutions up to 2560×1600 at a refresh rate of 60Hz. Dual-link connectors are fully backwards compatible with single-link operation unless a display mode uses more than 165MHz pixel clock frequency or 24 bits per pixel. In contrast, a single-link connector cannot support dual-link connections at any time; hence a dual-link connection is preferable in most cases.

DVI connection pins are comprised of the following potential components: parts of an 8×3 rectangle pinout supporting TMDS, DDC, analog vertical sync, power, hot plug detection and ground signals (Pin 1-24); 4 analog pins for RGB and horizontal sync (C1-C4); and a long flat pin for analog ground (C5).

DVI-A connectors have 17 (12+5) pins, do not have a dual-link option, and only carry analog signals. These signals are identical to VGA signals but are presented as an altered configuration. A VGA to DVI adapter is necessary to connect a VGA video card to a DVI-A monitor or a DVI-A video card to a VGA monitor. Due to VGA being the dominant connector for analog monitors and DVI as a standard for digital signals, DVI-A connectors are quite rare; instead, DVI-I and DVI-D connectors are more common. DVI-A cables will work with both DVI-A and DVI-I connectors. Male DVI-D cables may fit in a female DVI-A connector, but will not work as they do not carry any analog signals.

DVI-D connectors can only transfer digital video signals. Single-link DVI-D connectors have 19 pins (18+1) and dual-link DVI-D connectors have 25 pins (24+1). DVI-D cables will work with both DVI-D and DVI-I connectors. HDMI and DisplayPort connectors can support DVI-D video signals through an adapter, but DVI-D cannot support the additional features that HDMI and DisplayPort possess, such as integrated audio and CEC control. Most digital monitors have a DVI-D connector, while monitors which support both digital and analog signals usually have a DVI-D and VGA connector. Note that female DVI-D connectors will not accept male DVI-A or DVI-I cables as those connectors have the additional 4 analog pins that DVI-D lacks.

DVI-I single-link connectors have 23 pins (18+5) and dual-link connectors have 29 pins (24+5). DVI-I connectors do not convert analog and digital signals but can accept digital or analog signals – just not both at the same time. If a video card, monitor and cable all have DVI-I connections with the ability to support both analog and digital signals, one mode of operation has to be selected. True to their purpose, DVI-I connectors will work with all three DVI cable types. However, a male DVI-I cable will not fit in a female DVI-D connector due to its additional analog pins. Hence, when considering the rarity of a DVI-A connector, a DVI-D cable is the most commonly applicable out of the three cable types.

Check out NTI’s large selection of DVI products: extenders, video matrix switches, video splitters, KVM switches, and KVM Drawers.

This entry was posted in Insight and tagged A/V, audio, audio/video extension, connector, drawer, DVI, extender, extending a/v with existing wiring, KVM, matrix switch, splitter, switch, video, video signal. Bookmark the permalink.

DVI-D (24+1PIN) to D-SUB (VGA) Adapter

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  1. It's possible that certain GPUs have non-standard pinouts (I have a vague memory of hearing this, but am nowhere near certain).

    Other option is that if you stick one at each end, you can probably put DVI down a good VGA cable (which may prevent needing to rewire). Not quite sure; it appears that there are enough conductors for single link, but VGA appears to be a conductor and shield rather than twisted pair. Lots of errors at high data rates.
  2. Hi,

    If I understand correctly, DVI-D is supposed to make digital signal while DVI-I is supposed to make both digital and analog..
    All VGA displays are analog and can't receive digital signal (well.. they can but they don't understand it), so why would they manufacture something like this:
    http://www.ebay.com/itm/321551401999?_trksid=p2060778.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT
    What is it used for?


    That won't do anything.

    VGA doesn't provide power to the display of any kind, but DVI does. This means that it's theoretically possible for a DVI-D host to provide power to an active DVI-D to VGA converter but there's no mechanism to provide power to an active VGA to DVI-D converter without using an external power source. Of course, a passive DVI-A / DVI-I to VGA adapter or passive VGA to DVI-A adapter does not need power.

    I've seen a number of products from manufacturers that have no way to do what they describe.

    EDIT: Upon closer inspection it looks like that might do what I describe above, it can tap the +5v supply from the DVI port on the host to power a DVI-D to VGA converter.
  3. As it looks remarkably similar to the adapter I use on my 7790 I'm guessing it's just listed incorrectly. The symbol on the adapter is the same one found next to the DVI-I socket.
  4. Both DVI and VGA have a +5V power output, though it's optional on VGA and was originally used as a key pin.
  5. As it looks remarkably similar to the adapter I use on my 7790 I'm guessing it's just listed incorrectly. The symbol on the adapter is the same one found next to the DVI-I socket.


    It looks similar to what I have next to my DVI-D port. the DVI-I port has a (VGA) symbol next to it.
  6. That's the same symbol that is next to the DVI-I socket on both my 7790 and 660Ti's and I have used that kind of passive adapter on both at different times to run a VGA monitor.
  7. Hmm. My guess about a proprietary pinout on some GPUs is sounding likely.

    Is there a chance of you finding out what the wiring is on it? I'm kind of curious.
  8. As it looks remarkably similar to the adapter I use on my 7790 I'm guessing it's just listed incorrectly. The symbol on the adapter is the same one found next to the DVI-I socket.


    It looks similar to what I have next to my DVI-D port. the DVI-I port has a (VGA) symbol next to it.


    Different cards may be marked up differently it seems and there is no one right way, I don't think mine have both the VGA and digital symbol on them despite both having dual DVI sockets.





  9. It doesn't have the analog pins next to the flat blade, so it is a DVI-D.

    I did have a thought. Maybe VGA cables are cheaper over long distances? Run this and then back to DVI is cheaper for 50' runs?
  10. It doesn't have the analog pins next to the flat blade, so it is a DVI-D.

    I did have a thought. Maybe VGA cables are cheaper over long distances? Run this and then back to DVI is cheaper for 50' runs?


    I was going to say the same thing but the forums took a dump for most of the day yesterday. The lower picture is missing the C1 through C4 pins. This is consistent with a DVI-D male connector. I still suspect that it's drawing current from the +5 volt standby supply but this is dangerous to do. The +5 volt supply on DVI is only required to deliver at least 55 milliamps and the display itself can draw up to 50 milliamps. Inserting the converter in the middle may divert enough current that the display can no longer draw the 50 milliamps that it's allowed to which can cause compatibility problems.
  11. For that price, there is zero chance it's an active converter. It won't be drawing power, and ~50mA wouldn't be nearly enough if it was.

    My guess is it is simply a proprietary (not for this specific manufacturer, but a larger company made it and these guys are copying) pinout. I think some of the graphics card manufacturers were doing this for whatever reason.
  12. If you scroll down on the ebay listing, it has a picture of the DVI end. A DVI-D end.

    A similar adapter can be found on Amazon, with a mix of working and non-working reviews. Not sure how many are shills; at least some appear to be.
  13. If you scroll down on the ebay listing, it has a picture of the DVI end. A DVI-D end.

    A similar adapter can be found on Amazon, with a mix of working and non-working reviews. Not sure how many are shills; at least some appear to be.


    Ahh I see where you are coming from, it could just be the angle the picture is taken at as those pins are quite easy to hide if you tilt the adapter at the right angle.



    See what I mean?
  14. If you scroll down on the ebay listing, it has a picture of the DVI end. A DVI-D end.

    A similar adapter can be found on Amazon, with a mix of working and non-working reviews. Not sure how many are shills; at least some appear to be.


    Ahh I see where you are coming from, it could just be the angle the picture is taken at as those pins are quite easy to hide if you tilt the adapter at the right angle.



    See what I mean?


    Good catch. On closer inspection the C5 pin (the blade) appears to be wide and a pin just above and below it appear to be just barely visible. It may be miscategorized.
  15. I've already received the item 2 weeks ago (stupid huh?) and it doesn't have the extra 4 pins that are supposed to be with the DVI-I version of the adapter. Exactly like what you see in the picture.
  16. I've already received the item 2 weeks ago (stupid huh?) and it doesn't have the extra 4 pins that are supposed to be with the DVI-I version of the adapter. Exactly like what you see in the picture.


    Do they work as VGA/DVI adapters then?
  17. I've tested it with my old AMD HD 7750 which has a DVI-D port and it didn't work.. I didn't test it with my R9 280X (which has both DVI-D and DVI-I ports) since I use a DVI-I adapter currently (which works perfectly).
    I suppose it won't work but I'll give it a try with the new card this weekend and report back.
    My monitor is Samsung LED S22D300NY BTW.
  18. I've tested it with my old AMD HD 7750 which has a DVI-D port and it didn't work.. I didn't test it with my R9 280X (which has both DVI-D and DVI-I ports) since I use a DVI-I adapter currently (which works perfectly).
    I suppose it won't work but I'll give it a try with the new card this weekend and report back.
    My monitor is Samsung LED S22D300NY BTW.


    Without those four pins around the blade it's not going to work.
  19. Given it's about a $2 purchase, any chance of cracking it open and showing us the pinout? I'm curious as to what they did.
  20. Given it's about a $2 purchase, any chance of cracking it open and showing us the pinout? I'm curious as to what they did.


    I'll see if I can do that this weekend.

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