Need advice re projector with Vostro

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I have a new Dell Vostro A860.   I need to get a projector for
classroom use.   What do I need to know to select a projector that's
compatible ?

Re: Need advice re projector with Vostro

Zayde wrote:
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1) It should work with the connector standard on the laptop.
    The "Setup and Quick Reference Guide", shows the connector as
    being a 15 pin VGA.

2) The projector should support DDC/CI and EDID. (Some Display
    control panels, restrict the max resolution if that is not
    available. Probably not a problem, but it is still useful to

    DDC is a serial data channel on the cable.
    EDID is a table of data, going from the display device
    (your projector) to the laptop. It tells the laptop,
    what resolutions the projector supports.

    If you have DDC/CI and EDID, the projector is "Plug and Play"

While you can use devices without DDC, more hair-pulling is

Perhaps once you've costed out a solution, you could post
back the make and model number, for final comments ?


Just for fun, I picked a device at random.

This has just about every standard you could think of, on the back
panel. It includes a "D-sub" connector (VGA 15 pin).

NEC Display Solutions NP3151W 1280 x 800 LCD Projector  $4500.00

This is the user manual.

On PDF page 28 (paper page 14), it says:

    "Note: The COMPUTER 1 IN connector supports Plug & Play (DDC2)"

So that means the (mini) VGA connector supports Plug and Play information.

The native resolution of the projector is 1280 x 800, so that is
what you'd want coming from the laptop. For best compatibility with
video outputs, the first number should be divisible by 8, and the
second number divisible by 2. So that resolution passes that test.
Now, it is a question of how much of a hassle it'll be, to get the
laptop to actually output that value.

I can't find a reference, that gives a list of resolutions for the
GM965. The laptop LCD panel could be 1280x800, which would then
suggest it won't be a problem for the laptop to drive the projector.
If the projector has some weird horizontal or vertical native
resolution, then it is going to be tougher to get the laptop to
put out that resolution. You can try checking in the Display
control panel, but being Intel, I can't promise what you'll find.
(My ATI card lists some resolutions in a pull down box.)

Maybe you could connect up an existing monitor with VGA connector,
and do some initial testing to see what is available.

On desktop video cards, you can solve the custom video resolution
problem, by using Powerstrip from . But that
tool doesn't support laptop chipsets. Which means you're more dependent
on the Intel driver for the GM965 and whatever modes Intel chooses
to support. (The hardware is pretty flexible, and an OS like Linux
has been known to get more from the chipsets, than in Windows.)
With Powerstrip, you should be able to set anything that is
divisible by 8, divisible by 2. (The divisible by 8 rule is a
throwback to when frame buffers only put out 8 bit wide characters.
It is possible with digital outputs, to get down to the bit level,
by using an external TMDS transmitter on the GPU. But it is too
hard to get info, as to which computer video outputs support it.)

The projector will look best, if driven at its native resolution.
That makes text look nicer. If you were playing video, it might
not be as important. With video, you'd want an output resolution
with the same aspect ratio.


I haven't addressed the optical requirements. You need a certain
level of light output from the projector, need to select a lens
for the expected distance from projector to screen, and so on.
Someone familiar with AV installations or Home Theatre, may be
able to give you a ballpark figure as to what to expect to pay
for a projector.


Re: Need advice re projector with Vostro

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Epson PowerLite 1735W looks reasonably priced compared to other 3000
lumen projectors and has been well reviewed.   Epson tech support told
me that it is plug-and-play with USB input.
The native resolution is 1280 x 800. My laptop will do 1280 x 768.
Is that close enough ?
Any other advice ?

Re: Need advice re projector with Vostro

Zayde wrote:

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    (Spec sheet)

    (User manual - resolutions on PDF page 146)

You could try driving it at 1400 x 900 (which is aspect ratio 1.6),
and rely on resizing.

The thing is, for absolute best reproduction of an image, you
want one pixel on input, to give one pixel on the screen. Resizing
to arbitrary resolution is acceptable for video, but becomes
a problem as you present text with smaller and smaller point size.
If you expect to present 5 point font on the screen, it might not
be readable if the projector is resampling the image.

1) USB option should give excellent results for static images.
    It might be less desirable for movie playback (compression may
    not handle action scenes well, and there are limits to practical
    USB2 bus bandwidth). I would think the "USB stick" canned presentation
    thing would work well, because they could target the native

2) VGA option should have fewer performance limitations. If you
    drive it at 1280 x 800, you'll be getting every ounce of performance
    it has to offer. If you use some other resolution, you get best
    results (a circle looks like a circle), if the same aspect
    ratio is used. If you use 1280 x 768, one of two things
    can happen. Either the vertical will be stretched to fill
    the screen, or black bars will be inserted top and bottom.
    Black bars would be best, because they'd preserve 1:1 pixels.
    Stretch might not look so good. I've read, that some resolution
    choices, which have small differences from the ideal, have
    "tearing" or "moire" effects.

Since the review reports the measured contrast ratio of the
projector is 154:1 , I'd want to see it in person, before
buying it. If the vendor has a generous return policy, then
buying over the Internet may be OK. We had a projector at
work, that has that "washed out" look, and I'd want to
verify that this isn't the case here.

Still, the device has an interesting feature set, and for the
business trip/PowerPoint application, I think it would be
pretty good. But if you had some other plans for it,
then you may want to look it over more carefully.

The preferred interface might have been DVI, in the sense
that it offers lossless transmission from computer to
projector. At these low resolutions, VGA analog should be
indistinguishable, as it is isn't likely there'd be
cable signal reflections or distortion. So it should
still give excellent results.

I always try to drive LCDs at native resolution, if I can
possibly find a way. (For example, my current LCD monitor
has been run at native resolution, for the entire six years
I've had it.) I'm not a big fan of resampling. I tried the
next resolution down, and it was only good for games.

Another thing you can check into, if you want to, is
check the Dell site, and see if the video driver for
the Vostro A860, is more recent than your current video
driver. Intel has, on occasion, added extra resolution
choices via newer driver versions. Powerstrip would be
the other solution, but I don't know what progress has been
made on support for laptop graphics.

If you have the time to spend, you can look through the
forums at entechtaiwan. They spend a lot of time over
there, working on ways to get the resolutions people
are looking for in their equipment.

In that thread, they offer this link. Have fun :-) :-) /


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