From: tpang@fraser.sfu.ca (Tsui Ting Debbie Pang)
Subject: Re: REALLY confused about monitors - for a1200
Organization: Simon Fraser University, Burnaby, B.C., Canada
Date: Mon, 16 Nov 1992 11:52:39 GMT

kevinm@ocf.berkeley.edu (Kevin Miller) writes:
>Here's the way I understand it.  If I've made any mistakes, feel free to 
>correct me.
>>    1280 x 400
>Will work on 1084 (interlaced) or VGA (non-i)
No. 1280x400 can only be outputed as 15kHz, thus 1084 or multisync 
monitor which can sync at that freq. only.

>>    1280 x 200
>Will work on 1084 (with scan lines) and VGA (no scan lines). Games will not 
>work with VGA monitor.
No again. same answer as above. What game doesn't work? There are no
1280x200 mode games as I know, but if there is, it has nothing to do with
the monitor. Again, same answer as above for 1280x400.

>>    800 x 600
>Multi-sync required.
Only multisync which includes 24kHz! Not all multisync.

>>    640 x 690
>MS required.
Not just multisync, but at 31kHz, and even that, not all monitors work
with the Productivity mode (like mine, which handles the 3000 well in
HiRes and with Interlaced thru the deinterlacer, but not productivity
mode, due to the circuit design inside the analog section of the monitor).

>>    640 x 480
>1084 (interlaced), VGA (non-interlaced)
Wrong again. 1084 cannot handle any 640x??? mode. See answer above again.

>>    640 x 400
>Same as 640x400
I can't say you are wrong this time :). But you are not answering the
question either. This mode works with 15kHz only unless you add a
deinterlacer. So 1084 only.

>>    640 x 200
>Same as 320x200
Of course the frequencies are same! But you are not answering the right
way. See answer as above, same. 

>>    320 x 400
>>    320 x 200
>1084 will work with both, but 320x400 will flicker and 320x200 will have scan
>lines.  VGA will work wil both, without flicker and scan lines.  In general,
>games will not run if you use the VGA monitor because they games
>don't tell the computer to promote the screen.
What need to be promoted? This has nothing to do with promotion. The above
modes are only for 1084 unless you add a deinterlacer. same answer above.
> 
>>    All modes offer 256,000 colours from a palette of 16.7m.

>Yep.
I have to check on that on the productivity mode.

>>    Would a SVGA monitor be able to DISPLAY all of these, 
>>    with/without flicker?
Most SVGA monitors on the market are not able to sync down to 15kHz, they
start at 30kHz in general. Unless you add a deinterlacer, these are not
that useful.

>>    Would a multisync be able to DISPLAY all of these 
>>    with/without flicker?
>>Would the 'standard' C= 1084 monitor work ok?

>A proper multi-sync will work in all modes (like the C= 1960), but opting
>for either a VGA or 1084 limits you to certain modes. If you have the money,
>get the MS; otherwise look at the screens that the 104 and VGA screen will
>give you and choose.
In general, you are right for the first time! Congratulation :)

>>If anyone could explain what overscan and interlace mean,
>>and what they would mean to a user, I would also be grateful.

>Interlace is a way of displaying images.  Non-interlaced images are displayed
>line after line.  Interlaced images are a little differen: First the odd lines
>are displayed, and then the computer/monitor goes back and displays the even
>lines.  This causes the characteristic "flicker" that most people hate.  

Only because of using discrete contrast lines like on computer. How many
of you complain of watching TV? which is interlace?

>Flicker in the 640x400 modes will be worse than flicker in the 800x600 modes.
Because it is a lower refresh rate.
> 
>Overscan means that the screen goes beyond the edge of the viewable monitor 
>space.  This is the case on TV's for example.  Look at most IBM clones.  There
>will be a 1" or so strip all around the screen that it black.  An overscan
>screen would have the image fill the entire screen plus a little more.  This
>is very important for video work.

I think a lot of the answers are not quite correct on what monitors will
work, and I think I need to try to made a few corrections. I think we
should consider that people read information here and believe it. Therefore,
we should be responsible and not reply questions without checking the facts.
This is no flame, I just think it is dangerous to answer people asking
questions(especially basic things) the wrong answers.

This reminded me of yesterday, a customer walked into the computer store
I work, he has been given all the wrong information on SVGA monitors and
"interlaced" and "non-interlaced" monitors. He thinks a 70Hz monitor is
non-interlaced, and that's what he wants. He insisted that the monitor
we have (an AST) is only 60Hz because that's what it says on the back
(next to 120VAC, you know), even I explained the AC line frequency has
nothing to do with the video input refresh rate (not like long time ago),
he still says he would rather buy an ATi monitor since it is 70Hz and
thus non-interlaced. This gentleman is not computer iliterate, but it
is worse because he thinks he knows, which he isn't. I almost said to
him that the next thing he would tell me is that the earth is actually
flat since when he looks around, he can see it's flat.


David Tse

Organization: Sophomore, Math/Computer Science, Carnegie Mellon, Pittsburgh, PA