simultaneous analog and digital output from DVI-I
Hi,

I am trying to drive an LCT TV (with VGA input) and a DVI-D monitor via a splitter attached to the DVI-I out on my 7950GTX.

The splitter is definitely working in principle, as either display will work if it is the only one connected.

When both are connected however, only the digital display shows anything, analog remains blank. Although I would like both on at the same time, would actually be ok if I could just choose which one - but the only way to get the analog display working is to physically disconnect the digital one.

Grateful for any ideas.

Regards,
Dan
Hi,



I am trying to drive an LCT TV (with VGA input) and a DVI-D monitor via a splitter attached to the DVI-I out on my 7950GTX.



The splitter is definitely working in principle, as either display will work if it is the only one connected.



When both are connected however, only the digital display shows anything, analog remains blank. Although I would like both on at the same time, would actually be ok if I could just choose which one - but the only way to get the analog display working is to physically disconnect the digital one.



Grateful for any ideas.



Regards,

Dan

#1
Posted 02/06/2008 09:22 PM   
[quote name='dan_j_carter' date='Feb 6 2008, 05:22 PM']Hi,

I am trying to drive an LCT TV (with VGA input) and a DVI-D monitor via a splitter attached to the DVI-I out on my 7950GTX.

The splitter is definitely working in principle, as either display will work if it is the only one connected.

When both are connected however, only the digital display shows anything, analog remains blank. Although I would like both on at the same time, would actually be ok if I could just choose which one - but the only way to get the analog display working is to physically disconnect the digital one.

Grateful for any ideas.

Regards,
Dan
[right][snapback]321725[/snapback][/right]
[/quote]
Good luck with that - you're basically asking the impossible.

And why aren't you using the second port off the card, anyway?...
[quote name='dan_j_carter' date='Feb 6 2008, 05:22 PM']Hi,



I am trying to drive an LCT TV (with VGA input) and a DVI-D monitor via a splitter attached to the DVI-I out on my 7950GTX.



The splitter is definitely working in principle, as either display will work if it is the only one connected.



When both are connected however, only the digital display shows anything, analog remains blank. Although I would like both on at the same time, would actually be ok if I could just choose which one - but the only way to get the analog display working is to physically disconnect the digital one.



Grateful for any ideas.



Regards,

Dan

[snapback]321725[/snapback]




Good luck with that - you're basically asking the impossible.



And why aren't you using the second port off the card, anyway?...

Intel Siler DX79SI Desktop Extreme | Intel Core i7-3820 Sandy Bridge-Extreme | DangerDen M6 and Koolance MVR-40s w/Black Ice Stealths | 32 GB Mushkin PC3-12800LV | NVIDIA GTX 660 Ti SLI | PNY GTX 470 | 24 GB RAMDisk (C:\Temp\Temp) | 120 GB Intel Cherryville SSDs (OS and UserData)| 530 GB Western Digital VelociRaptor SATA 2 RAID0 (C:\Games\) | 60 GB G2 SSDs (XP Pro and Linux) | 3 TB Western Digital USB-3 MyBook (Archive) | LG BP40NS20 USB ODD | LG IPS236 Monitor | LogiTech X-530 Speakers | Plantronics GameCom 780 Headphones | Cooler Master UCP 1100 | Cooler Master HAF XB | Windows 7 Pro x64 SP1

Stock is Extreme now

#2
Posted 02/07/2008 03:03 AM   
[quote name='jaafaman' date='Feb 7 2008, 04:03 AM']Good luck with that - you're basically asking the impossible.

And why aren't you using the second port off the card, anyway?...
[right][snapback]321840[/snapback][/right]
[/quote]

Thanks for reply - Perhaps I wasn't clear, I want the same image on analog and digital, same resolution etc: Are you saying this is impossible ? if so maybe you could explain why so I don't try anything else stupid.

The second port is in use for another monitor (dualview) - What I want is a dual view setup with the secondary monitor cloned onto a big LCD for presentations etc.
[quote name='jaafaman' date='Feb 7 2008, 04:03 AM']Good luck with that - you're basically asking the impossible.



And why aren't you using the second port off the card, anyway?...

[snapback]321840[/snapback]






Thanks for reply - Perhaps I wasn't clear, I want the same image on analog and digital, same resolution etc: Are you saying this is impossible ? if so maybe you could explain why so I don't try anything else stupid.



The second port is in use for another monitor (dualview) - What I want is a dual view setup with the secondary monitor cloned onto a big LCD for presentations etc.

#3
Posted 02/07/2008 10:10 AM   
I've used the cables you are describing.
Ithink the problem is that you are using DVI to driver DVI and VGA. Not a good plan.

The VGA and DVI signals are different and the card detects which to output. It's detected the DVI signal and output that. The VGA monitor won't understand.

However, you can use the second port on the card and nView. nView gives you different modes that you can use

Clone, mirror one desktop on both monitors (both ports). The problem here is that both monitors have to support the same resolution.

Stretch, this stretches the desktop across both monitors. Not really what you are after

DualView. This gives you 2 seperate desktops. This might acutally suit you. They can have different resolutions and have different window. You can maximise the presentation on the big screen and keep speakers notes on the desktop. Thats if the speaker can see enough of the big screen to still control it. I have seen custom apps the provide a small control pad on the PC monitor and the main image on the big display.

I would try clone mode and tweak from there
I've used the cables you are describing.

Ithink the problem is that you are using DVI to driver DVI and VGA. Not a good plan.



The VGA and DVI signals are different and the card detects which to output. It's detected the DVI signal and output that. The VGA monitor won't understand.



However, you can use the second port on the card and nView. nView gives you different modes that you can use



Clone, mirror one desktop on both monitors (both ports). The problem here is that both monitors have to support the same resolution.



Stretch, this stretches the desktop across both monitors. Not really what you are after



DualView. This gives you 2 seperate desktops. This might acutally suit you. They can have different resolutions and have different window. You can maximise the presentation on the big screen and keep speakers notes on the desktop. Thats if the speaker can see enough of the big screen to still control it. I have seen custom apps the provide a small control pad on the PC monitor and the main image on the big display.



I would try clone mode and tweak from there

#4
Posted 02/07/2008 10:47 AM   
[quote name='dan_j_carter' date='Feb 7 2008, 06:10 AM']Thanks for reply - Perhaps I wasn't clear, I want the same image on analog and digital, same resolution etc: Are you saying this is impossible ? if so maybe you could explain why so I don't try anything else stupid.

The second port is in use for another monitor (dualview) - What I want is a dual view setup with the secondary monitor cloned onto a big LCD for presentations etc.
[right][snapback]322022[/snapback][/right]
[/quote]
You cannot transmit a data signal at the same time you do an analog. That's why you have two ports to support two monitors. And it's why you can test each singly but not together.

[i]If you wish to split a single port's signal, both monitors must be of the same type[/i], because both must use the same signal type...
[quote name='dan_j_carter' date='Feb 7 2008, 06:10 AM']Thanks for reply - Perhaps I wasn't clear, I want the same image on analog and digital, same resolution etc: Are you saying this is impossible ? if so maybe you could explain why so I don't try anything else stupid.



The second port is in use for another monitor (dualview) - What I want is a dual view setup with the secondary monitor cloned onto a big LCD for presentations etc.

[snapback]322022[/snapback]




You cannot transmit a data signal at the same time you do an analog. That's why you have two ports to support two monitors. And it's why you can test each singly but not together.



If you wish to split a single port's signal, both monitors must be of the same type, because both must use the same signal type...

Intel Siler DX79SI Desktop Extreme | Intel Core i7-3820 Sandy Bridge-Extreme | DangerDen M6 and Koolance MVR-40s w/Black Ice Stealths | 32 GB Mushkin PC3-12800LV | NVIDIA GTX 660 Ti SLI | PNY GTX 470 | 24 GB RAMDisk (C:\Temp\Temp) | 120 GB Intel Cherryville SSDs (OS and UserData)| 530 GB Western Digital VelociRaptor SATA 2 RAID0 (C:\Games\) | 60 GB G2 SSDs (XP Pro and Linux) | 3 TB Western Digital USB-3 MyBook (Archive) | LG BP40NS20 USB ODD | LG IPS236 Monitor | LogiTech X-530 Speakers | Plantronics GameCom 780 Headphones | Cooler Master UCP 1100 | Cooler Master HAF XB | Windows 7 Pro x64 SP1

Stock is Extreme now

#5
Posted 02/07/2008 11:09 AM   
[quote name='cosmicnut' date='Feb 7 2008, 11:47 AM']I've used the cables you are describing.
Ithink the problem is that you are using DVI to driver DVI and VGA. Not a good plan.

The VGA and DVI signals are different and the card detects which to output. It's detected the DVI signal and output that. The VGA monitor won't understand.

However, you can use the second port on the card and nView. nView gives you different modes that you can use

Clone, mirror one desktop on both monitors (both ports). The problem here is that both monitors have to support the same resolution.

Stretch, this stretches the desktop across both monitors. Not really what you are after

DualView. This gives you 2 seperate desktops. This might acutally suit you. They can have different resolutions and have different window. You can maximise the presentation on the big screen and keep speakers notes on the desktop. Thats if the speaker can see enough of the big screen to still control it. I have seen custom apps the provide a small control pad on the PC monitor and the main image on the big display.

I would try clone mode and tweak from there
[right][snapback]322032[/snapback][/right]
[/quote]


cosmicnut, thanks for reply:

None of the modes you mention help me here - I am driving 3 screens not 2. To clarify, I now have a partial solution - instead of using the DVI-I -> vga + DVI-D splitter, I am using a DVI-I -> 2*DVI-D splitter, and feeding the second split DVI-D to the HDMI port on the LCD TV. This works exactly as I want, monitor 1 showing 1 thing, monitor 2 and LCD TV showing the other. The only problem is that the TV supports a lower resolution than possible via VGA.

I guess I am just not going to do any better than this.
[quote name='cosmicnut' date='Feb 7 2008, 11:47 AM']I've used the cables you are describing.

Ithink the problem is that you are using DVI to driver DVI and VGA. Not a good plan.



The VGA and DVI signals are different and the card detects which to output. It's detected the DVI signal and output that. The VGA monitor won't understand.



However, you can use the second port on the card and nView. nView gives you different modes that you can use



Clone, mirror one desktop on both monitors (both ports). The problem here is that both monitors have to support the same resolution.



Stretch, this stretches the desktop across both monitors. Not really what you are after



DualView. This gives you 2 seperate desktops. This might acutally suit you. They can have different resolutions and have different window. You can maximise the presentation on the big screen and keep speakers notes on the desktop. Thats if the speaker can see enough of the big screen to still control it. I have seen custom apps the provide a small control pad on the PC monitor and the main image on the big display.



I would try clone mode and tweak from there

[snapback]322032[/snapback]








cosmicnut, thanks for reply:



None of the modes you mention help me here - I am driving 3 screens not 2. To clarify, I now have a partial solution - instead of using the DVI-I -> vga + DVI-D splitter, I am using a DVI-I -> 2*DVI-D splitter, and feeding the second split DVI-D to the HDMI port on the LCD TV. This works exactly as I want, monitor 1 showing 1 thing, monitor 2 and LCD TV showing the other. The only problem is that the TV supports a lower resolution than possible via VGA.



I guess I am just not going to do any better than this.

#6
Posted 02/07/2008 05:01 PM   
[quote name='jaafaman' date='Feb 7 2008, 12:09 PM']You cannot transmit a data signal at the same time you do an analog. That's why you have two ports to support two monitors. And it's why you can test each singly but not together.

[i]If you wish to split a single port's signal, both monitors must be of the same type[/i], because both must use the same signal type...
[right][snapback]322038[/snapback][/right]
[/quote]

jaafaman, thanks - that's useful info.

Given the cable I have (from ebay) is specifically DVI-I at one end, and 1 DVI-D and 1 VGA at the other end, you are saying this cable is inherently pointless as it can never work ?

Thanks again.
[quote name='jaafaman' date='Feb 7 2008, 12:09 PM']You cannot transmit a data signal at the same time you do an analog. That's why you have two ports to support two monitors. And it's why you can test each singly but not together.



If you wish to split a single port's signal, both monitors must be of the same type, because both must use the same signal type...

[snapback]322038[/snapback]






jaafaman, thanks - that's useful info.



Given the cable I have (from ebay) is specifically DVI-I at one end, and 1 DVI-D and 1 VGA at the other end, you are saying this cable is inherently pointless as it can never work ?



Thanks again.

#7
Posted 02/07/2008 05:04 PM   
I was just thinking the same thing. I just bought a DVI-I to VGA & DVI-D adapter. I then put a VGA splitter on the VGA port of the original splitter, and cloned my 2nd monitor to a LCD TV. It works at 1280 X 720 which is understandable since they are different monitors and the TV only goes to 768. But the DVI-D portion of the original splitter does not output anything to my DVI-D connected projector. Even if I take off the 2nd VGA splitter, only connect one monitor to the VGA side, the DVI-D puts nothing out. Thats as basic as it gets to "use" this type of adapter, but i guess it is "useless".... I was reading another post about being able to control the output of digital and analog with registry settings, I guess this is all for nothing if DVI-I cannot output VGA and DVI-D at the same time. Wonder if its possible, just not with Nvidia drivers etc.
I was just thinking the same thing. I just bought a DVI-I to VGA & DVI-D adapter. I then put a VGA splitter on the VGA port of the original splitter, and cloned my 2nd monitor to a LCD TV. It works at 1280 X 720 which is understandable since they are different monitors and the TV only goes to 768. But the DVI-D portion of the original splitter does not output anything to my DVI-D connected projector. Even if I take off the 2nd VGA splitter, only connect one monitor to the VGA side, the DVI-D puts nothing out. Thats as basic as it gets to "use" this type of adapter, but i guess it is "useless".... I was reading another post about being able to control the output of digital and analog with registry settings, I guess this is all for nothing if DVI-I cannot output VGA and DVI-D at the same time. Wonder if its possible, just not with Nvidia drivers etc.

#8
Posted 02/15/2008 05:06 AM   
I just verfied all cables work, and was able to get the DVI-D working by itself with the projector. Plugged in the VGA monitor on the other side when DVI-D side was up and going....nothing.
I just verfied all cables work, and was able to get the DVI-D working by itself with the projector. Plugged in the VGA monitor on the other side when DVI-D side was up and going....nothing.

#9
Posted 02/15/2008 05:25 AM   
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