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Keegan Alex

External


Since: Jul 12, 2003
Posts: 1



(Msg. 1) Posted: Sat Jul 12, 2003 3:33 pm
Post subject: Using an older CGA monitor on newer computer
Archived from groups: comp>sys>ibm>pc>hardware>video (more info?)
Hi folks,

I'm setting up a non-GUI Linux box, and this seems to be the perfect
thing for my old IBM monitor (5053), which is CGA. Problem is the
computer I'll be using has no ISA or EISA slots, so my good'ol CGA
card won't work.

If I get a DB15 to DB9 adapter, can any older VGA card work? This
will be only command line Linux, so no graphics... only basic colors
if possible. Or, if anyone knows how to pin-out the DB15 VGA slot to
a DB9 CGA monitor, that'd work.

Thanks,

Keegan.

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J.Clarke

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Since: Nov 08, 2003
Posts: 160



(Msg. 2) Posted: Sat Jul 12, 2003 9:06 pm
Post subject: Re: Using an older CGA monitor on newer computer [Login to view extended thread Info.]
Archived from groups: per prev. post (more info?)
On 12 Jul 2003 12:33:42 -0700
keeganalex.DeleteThis@yahoo.com (Keegan Alex) wrote:

 > Hi folks,
 >
 > I'm setting up a non-GUI Linux box, and this seems to be the perfect
 > thing for my old IBM monitor (5053), which is CGA. Problem is the
 > computer I'll be using has no ISA or EISA slots, so my good'ol CGA
 > card won't work.
 >
 > If I get a DB15 to DB9 adapter, can any older VGA card work? This
 > will be only command line Linux, so no graphics... only basic colors
 > if possible. Or, if anyone knows how to pin-out the DB15 VGA slot to
 > a DB9 CGA monitor, that'd work.

Not going to work. IBM changed the signalling method when they
introduced the VGA. The CGA used 4-bit digital signalling, the VGAs are
analog--they can't drive the IBM Color Display, the IBM Monochrome
Display, or the IBM Enhanced Color Display. Best bet would be to set the
Linux box up for serial I/O then use an ISA machine as a terminal, if
you're determined to use that monitor. Personally I'd rather pay 50
bucks or so for a used VGA monitor than look at an IBM Color Display for
any length of time, especially if it's text. Did too much of that in my
misspent youth.

 > Thanks,
 >
 > Keegan.


--
--
--John
Reply to jclarke at ae tee tee global dot net
(was jclarke at eye bee em dot net)<!-- ~MESSAGE_AFTER~ -->

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e3rrew

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Since: Jul 12, 2003
Posts: 2



(Msg. 3) Posted: Sun Jul 13, 2003 1:47 am
Post subject: Re: Using an older CGA monitor on newer computer [Login to view extended thread Info.]
Archived from groups: per prev. post (more info?)
 > I'm setting up a non-GUI Linux box, and this seems to be the perfect
 > thing for my old IBM monitor (5053), which is CGA. Problem is the
 > computer I'll be using has no ISA or EISA slots, so my good'ol CGA
 > card won't work.
 >
 > If I get a DB15 to DB9 adapter, can any older VGA card work?

NO NO NO NON ONONON NONONON NONONO NON ONO NO NO NO NO NON ON ON ON

CGA (and EGA) monitors use digital TTL (transistor-transistor-logic)
signalling levels. VGA-adapters spit out analog-signal levels (0.7vpp,
if I'm not mistaken.) Not to worry, I'm pretty sure the CGA/EGA
TTL-signalling levels are +3.3 or 5v peaks, so your VGA card won't
damage the monitor.

 > This
 > will be only command line Linux, so no graphics... only basic colors
 > if possible. Or, if anyone knows how to pin-out the DB15 VGA slot to
 > a DB9 CGA monitor, that'd work.

Sorry, you'd need a video-card (like your ISA CGA or EGA card) with
the proper electrical interface. Merely converting the VGA's DB15
to DB9 connector-form isn't enough. There used to be some ancient
(ISA) VGA-cards with EGA capability. My ATI VGAWonder had both
subD (VGA) connector and a DB9 connector for CGA/EGA monitors. You
could only use one connector at a time (the video BIOS scanned the
ports during POST.)

Note, I'm not even going to go into the other half of proper CGA/EGA
support, which is the video-mode scan-rates. VGA-text is scanned
at 31.5KHz (720x400, 70Hz), whereas IBM EGA scanned text at something
like 640x350 (60Hz.) And of course, CGA was even more limited...
640x200 (60Hz.) The ATI VGAWonder's BIOS properly programmed the
dot-clocks for the selected mode (CGA, EGA, VGA.) Failing to do this,
you *can* damage an old monitor. (Old monitors have stupid
electronics which aren't smart enough to shutdown the CRT-gun
if the input-signal is out of range.)

 > NO NO NO NON ONONON NONONON NONONO NON ONO NO NO NO NO NON ON ON ON

heh, that came out kind of funny. Well I hope it made you laugh
as much as it made me laugh...<!-- ~MESSAGE_AFTER~ -->
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Michael J. Apollyo

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Since: Nov 30, 2003
Posts: 49



(Msg. 4) Posted: Mon Jul 14, 2003 12:39 am
Post subject: Re: Using an older CGA monitor on newer computer [Login to view extended thread Info.]
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J.Clarke

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Since: Nov 08, 2003
Posts: 160



(Msg. 5) Posted: Mon Jul 14, 2003 1:03 am
Post subject: Re: Using an older CGA monitor on newer computer [Login to view extended thread Info.]
Archived from groups: per prev. post (more info?)
On Sun, 13 Jul 2003 21:39:57 GMT
"Michael J. Apollyon" <zvpunry.wb DeleteThis @ovtsbbg.pbz> wrote:

 > I don't know if it's possible, but this came up on a
 > Google search...
 >
<font color=purple> > <a style='text-decoration: underline;' href="http://www.converters.tv/products/converters/rgb_converters/40.html</font" target="_blank">http://www.converters.tv/products/converters/rgb_converters/40.html</font</a>>
 > or
<font color=purple> > <a style='text-decoration: underline;' href="http://tinyurl.com/gthe</font" target="_blank">http://tinyurl.com/gthe</font</a>>

That particular device seems to work by running the VGA signal through
an analog-to-digital converter. I suspect that it works fine, subject
to the resolution limits of the CGA, but you can get a new 17" CRT for
less money.

--
--
--John
Reply to jclarke at ae tee tee global dot net
(was jclarke at eye bee em dot net)<!-- ~MESSAGE_AFTER~ -->
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xby

External


Since: Jul 16, 2003
Posts: 2



(Msg. 6) Posted: Wed Jul 16, 2003 6:35 pm
Post subject: Re: Using an older CGA monitor on newer computer [Login to view extended thread Info.]
Archived from groups: per prev. post (more info?)
keeganalex.RemoveThis@yahoo.com (Keegan Alex) wrote in message news:<d815f41a.0307121133.1d47713.RemoveThis@posting.google.com>...
 > Hi folks,
 >
 > I'm setting up a non-GUI Linux box, and this seems to be the perfect
 > thing for my old IBM monitor (5053), which is CGA. Problem is the
 > computer I'll be using has no ISA or EISA slots, so my good'ol CGA
 > card won't work.
 >
 > If I get a DB15 to DB9 adapter, can any older VGA card work? This
 > will be only command line Linux, so no graphics... only basic colors
 > if possible. Or, if anyone knows how to pin-out the DB15 VGA slot to
 > a DB9 CGA monitor, that'd work.
 >
 > Thanks,
 >
 > Keegan.



In response to my query regarding the absence of ISA slots in new
mainboards, a person by the name of Pen posted the following reply
back on 2003-05-25:

"Mobos are available with ISA slots, here are a few;
The Soyo 'P4I 845PE ISA' motherboard, based on the i845PE
chipset supports 400 and 533MHZ FSB Pentium 4 processors.
3 ISA slots, 4 PCI slots, 1 AGP slot
Onboard video, sound, Ethernet and USB 2.0.
<a style='text-decoration: underline;' href="http://www.soyousa.com/products/proddesc.php?id=194" target="_blank">http://www.soyousa.com/products/proddesc.php?id=194</a>
Here's a supermicro one;
<a style='text-decoration: underline;' href="http://www.supermicro.com/PRODUCT/MotherBoards/875/P4SCA.htm" target="_blank">http://www.supermicro.com/PRODUCT/MotherBoards/875/P4SCA.htm</a>
Further, there seem to be several versions of the
Gigabyte GA-7ZX that have one ISA slot. The
-7ZXC is one of them. Unknow if this is current
production."

I hope that this information is useful for you.<!-- ~MESSAGE_AFTER~ -->
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