MBP Adding Another DVI Monitor

DJAKO

macrumors 6502a
Original poster
Sep 8, 2006
591
13
Michigan
Right now I have a 22.1in monitor hooked up using the DVI connection on my MBP. Is there another way to add another monitor? I've seen a few products such as

http://sewelldirect.com/vtbookpcmciacard.asp which seems like that would work, but is pretty expensive.

http://sewelldirect.com/USB-to-DVI-Adapter-1600x1200.asp# this guy is PC only the moment.

http://www.cablesunlimited.com/products/Prod_Individual3.aspx?groupcode=I3581 what about a DVI splitter? Would that do the trick?

Any other suggestions? Thanks.
 

rogersmj

macrumors 68020
Sep 10, 2006
2,158
0
Indianapolis, IN
I used to swear up and down that splitting DVI would not work (probably because it really didn't, at least for a time). However, just last week I was talking with my friend who has a new Santa Rosa MBP. He mentioned how he was using his two 19" Dell LCDs with it. I stopped him and asked him...

"Two external LCDs on a MacBook Pro? How do you have them hooked up?"

"DVI splitter."

"Well they're just displaying the same thing, aren't they?"

"No, I've got three distinct screens -- the two externals and the MBP screen."

I made him take a photograph of the setup and email me a screenshot of the System Preferences display panel -- even though I would trust this guy with my life, I just found this really hard to believe -- and it was true. He had three distinct screens seen by OS X with nothing more than a $20 DVI splitter.

I have no idea how this could work, because I know in the past (and everything I know about digital signals also tells me) this wasn't possible. I'd love it if someone could come up with a solid explanation for this.
 

admiraldennis

macrumors regular
Aug 19, 2002
239
0
Boston, MA
I used to swear up and down that splitting DVI would not work (probably because it really didn't, at least for a time). However, just last week I was talking with my friend who has a new Santa Rosa MBP. He mentioned how he was using his two 19" Dell LCDs with it. I stopped him and asked him...

"Two external LCDs on a MacBook Pro? How do you have them hooked up?"

"DVI splitter."

"Well they're just displaying the same thing, aren't they?"

"No, I've got three distinct screens -- the two externals and the MBP screen."

I made him take a photograph of the setup and email me a screenshot of the System Preferences display panel -- even though I would trust this guy with my life, I just found this really hard to believe -- and it was true. He had three distinct screens seen by OS X with nothing more than a $20 DVI splitter.

I have no idea how this could work, because I know in the past (and everything I know about digital signals also tells me) this wasn't possible. I'd love it if someone could come up with a solid explanation for this.
...

Can we please see this photograph and get a model number for the device?
 

rogersmj

macrumors 68020
Sep 10, 2006
2,158
0
Indianapolis, IN
OK here's the screenshot of his MBP's display preferences, and the DVI splitter he's using. I can't find the picture of the setup, he IM'd it to me via direct IM and I don't think I saved it.

The display preferences is showing the MBP's 1440x900 LCD and two 19" Dell 1280x1024 LCDs.
 

Attachments

DJAKO

macrumors 6502a
Original poster
Sep 8, 2006
591
13
Michigan
I just bought this guy, http://www.iogear.com/main.php?loc=product&Item=GVS162W6 at a local retail store today hoping it would fix my problem. After I set it up I only got it to mirror my display. So rather than having 3 distinct screens, I have only 2. Both my external monitors show the exact same thing. Is there any work around with this product? If not, I guess I'll have to return it.
 

danny_w

macrumors 601
Mar 8, 2005
4,380
127
Austin, TX
I don't think a DVI splitter like that is what you want. That sends a single DVI signal to two monitors. The MBP has 2 DVI signals on a single DVI shell; that is how it drives the Apple 30" display. What you need is a cable that splits out one signal to one monitor and the other signal to the other monitor. I don't know what this kind of cable is called, but it certainly should be possible; it is the same principle as a two-line telephone cable splitter that allows you to hook up 2 phones, one to each line.
 

rogersmj

macrumors 68020
Sep 10, 2006
2,158
0
Indianapolis, IN
What you need is a cable that splits out one signal to one monitor and the other signal to the other monitor.
That was exactly my theory about the splitter my friend has (see above) that allows him to run the two external single-link DVI monitors. It's the only way I can think of how it might possibly work. His office bought the DVI splitter though so he's not exactly sure where it came from. I'll see if he can dig up exactly what its model number is.
 

ab2650

macrumors 6502a
Jun 21, 2007
714
0
That was exactly my theory about the splitter my friend has (see above) that allows him to run the two external single-link DVI monitors. It's the only way I can think of how it might possibly work. His office bought the DVI splitter though so he's not exactly sure where it came from. I'll see if he can dig up exactly what its model number is.
You know what also might help are pictures of the ends of his cable (if he's willing to snap a few more pics). The pin pattern may give away if it's dual-link on the source side and single-link on the two output sides.

I've been thinking about laying out a few bucks to take a shot in the dark at some of these cables. So far I've found:

http://www.newegg.com/Product/Product.aspx?Item=N82E16812339004
and
http://www.monoprice.com/products/product.asp?c_id=101&cs_id=1011304&p_id=2518
 

rogersmj

macrumors 68020
Sep 10, 2006
2,158
0
Indianapolis, IN
You know what also might help are pictures of the ends of his cable (if he's willing to snap a few more pics). The pin pattern may give away if it's dual-link on the source side and single-link on the two output sides.
OK he's going to take detailed pics of the cable as soon he gets the MBP back (it's shared around the office sometimes and some other employee has it for a trip this week I guess). He's going to try to track down the exact cable via their purchase order in the meantime.
 

admiraldennis

macrumors regular
Aug 19, 2002
239
0
Boston, MA
OK he's going to take detailed pics of the cable as soon he gets the MBP back (it's shared around the office sometimes and some other employee has it for a trip this week I guess). He's going to try to track down the exact cable via their purchase order in the meantime.
Thanks for working to figure this out.

If this is legit, it'll be quite the exciting discovery.
 

rogersmj

macrumors 68020
Sep 10, 2006
2,158
0
Indianapolis, IN
Not yet...it may be a few days, like I said he doesn't have the laptop right now and I don't know how easy it is for him to get info from their purchasing department. But as soon as I know anything, I'll post back here.
 

gotzero

macrumors 68040
Jan 6, 2007
3,224
0
Mid-Atlantic, US
I am about to go out and start buying adaptors just to see if this will work. If I can power my 2x23"s from my MPB I will be SO happy.

I am becoming a big victim of monitor inflation, but I feel like it is never enough...

I just wish the mini had DVI-D so I could run a 30" or the possible 2X23" off of it.
 

DJAKO

macrumors 6502a
Original poster
Sep 8, 2006
591
13
Michigan
I am about to go out and start buying adaptors just to see if this will work. If I can power my 2x23"s from my MPB I will be SO happy.

I am becoming a big victim of monitor inflation, but I feel like it is never enough...

I just wish the mini had DVI-D so I could run a 30" or the possible 2X23" off of it.
I was in the same boat as you man. I bought three things and all of them did not do what I wanted. So I'm stuck again looking for another answer or help
 

ab2650

macrumors 6502a
Jun 21, 2007
714
0
I just wish the mini had DVI-D...
FWIW, the mini has DVI-I (digital + analog), which is 'greater than' DVI-D (digital only).
Me thinks what you meant to say is you wish it had DualLink DVI (so it could run a 30")

Someone correct me if I'm wrong.
 

TheStu

macrumors 65816
Aug 20, 2006
1,245
0
Carlisle, PA
FWIW, the mini has DVI-I (digital + analog), which is 'greater than' DVI-D (digital only).
Me thinks what you meant to say is you wish it had DualLink DVI (so it could run a 30")

Someone correct me if I'm wrong.
You are right in that it cannot run a 30"... not too sure about the DVI-I and whatnot.

And to the poster that wanted to run 2 23" displays... that would be greater total pixels than a single 30" display which is what the MBP is rated to run at max. So, you need something smaller than that. 2 20" displays would work.
 

gotzero

macrumors 68040
Jan 6, 2007
3,224
0
Mid-Atlantic, US
You are right in that it cannot run a 30"... not too sure about the DVI-I and whatnot.

And to the poster that wanted to run 2 23" displays... that would be greater total pixels than a single 30" display which is what the MBP is rated to run at max. So, you need something smaller than that. 2 20" displays would work.
I meant Dual-Link, sorry.

About the 2x23", I am hoping that it would run in clamshell without the internal display. I just have no need for a Mac Pro, and therefore cannot justify the costs... Right now, i have different systems on each display, but i would like to put them on one sometimes...
 
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