Re: macintosh rgb monitors

["Roger Johnstone" <rojaws@mac.com>]

In article <20010929192303.26652.00002721@mb-mq.aol.com>, nailslover@aol.com
(Nailslover) wrote:

> hi everyone,

> i have a apple rgb monitor (it says macintosh rgb on the back of it) and was
> wonderig if that would work with the apple 2gs?

Sorry, no it won't.

> i assume a apple rgb monitor is a apple rgb monitor whether it says mac on the
> back or not.

RGB just means it has an RGB interface i.e. the red, green and blue colour
information and the sync signals are sent seperately versus a composite
monitor where all the video signals are combined. The PC VGA, IIgs and Mac
displays are all RGB displays.

> i always thought that rgb referred to it being like 15 hz instead of vga's 31
> hz???

> thanks bo

That's the problem. The IIgs uses a scan frequency of about 15kHz, the same
as TVs use, which is why you can connect one to a TV, either via the
composite input or the RGB input on a SCART connector.

VGA was orignally about 31kHz, Mac colour monitors were orignally about
35kHz. Both of these have changed as resolutions have increased. Some of the
later Macs were even designed to sync down to 31kHz so Apple could supply
them with cheap VGA monitors, and some PC cards can do 35kHz to drive a Mac
monitor.

All monitors now are multifrequency and will automatically synchronise over
a wide frequency range, but normally won't go lower than 31kHz. There were
some older monitors which would sync down to 15kHz and can be used on a
IIgs, but I think the 'Macintosh RGB' is an old fixed-frequency monitor,
35kHz only.

--
Roger Johnstone, Invercargill, New Zealand

Apple II - Future Cop:LAPD - iMac Voodoo2 - Warcraft II
http://homepage.mac.com/rojaws
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As a computer, I find your faith in technology amusing