Spanning mulit-mode for laptop

July 28, 2005 8:45 AM

I have a laptop with a vga out - is there an external box or some sort of device that would allow me to have a spanning multi mode with two external monitors, in addition to the laptop?

Extended explanation: I'd like two use two external monitors with my laptop, and use the two external monitors as one display, not mirrored.

posted by The Jesse Helms to Computers & Internet (7 answers total)

VGA Splitter cable should do the trick. Your graphic driver software should be able to handle the display properties.
posted by prostyle at 8:52 AM on July 28, 2005

Erm, after reading some more random product pages it seems that a 'splitter' may be right in theory, but 'multiplier' may be more accurate in terms of keeping the two signals at full strength. You should be able to find them locally, whatever you decide to go with. Just thought I'd mention the discrepancy.
posted by prostyle at 8:55 AM on July 28, 2005

Best answer: A VGA splitter cable will just give the same picture on both monitors. What TJH needs is a USB to VGA adapter (assuming the laptop has VGA) to provide a separate output for the second external monitor.

Laptop screen - display 1
Laptop VGA port - display 2
USB VGA port - display 3

Windows should then be able to use all three displays separately or combinations thereof.
posted by mrbill at 9:04 AM on July 28, 2005

Er, that's "assuming the laptop has USB". We need an "edit" function.
posted by mrbill at 9:05 AM on July 28, 2005

mrbill: my gf's toshiba pentium 166mmx had a usb adapter. OTOH, I'd be curious to see the difference in performance of this device between USB 1.0 and 2.0, since it says it supports both.
posted by furtive at 10:31 AM on July 28, 2005

I can't imagine a USB to VGA converter would work really well--even USB2 bandwidth is low compared to what you'd need for a VGA of any decent size.

Usually, this is done one of two ways. First option: plug in an external monitor to the vga port. Depending on the VGA chipset(s) used, the laptop may be able to do this natively. Your results may vary depending on how it was implemented--so you may or may not be able to have a non-rectangular desktop as opposed to one big rectangle with a single taskbar spanning them (blech, usually). I think it has to do with whether they use two distinct chipsets in there or not. I used to run this way.

You also may (depending on manufacturer) be able to buy a docking station for your laptop that accepts PCI cards. Then, you can just buy a PCI video adapter. This is what I currently do. My dock has its own video out from the laptop, and it also has a card with two more ports for a total of three displays, all external. This works pretty well. A disadvantage of this setup is that I can't undock withough completely shutting down as you're essentially hotswapping PCI cards, which doesn't generally work. :)
posted by RikiTikiTavi at 7:24 AM on July 29, 2005

They do exist, but only recently. USB 2 is an absolute must, and even still does a mediocre job. Tom's Hardware review.

PCMCIA VGA cards can offer quite reasonable performance.

Another option, if you have a spare computer is MaxiVista, software that allows you to use one computer's monitors as extras for another.
posted by SpookyFish at 7:48 PM on July 29, 2005