5150/5151 Video Card??

Chuck Guzis cclist at sydex.com
Mon Aug 15 00:47:14 CDT 2016

On 08/14/2016 10:15 PM, Fred Cisin wrote:

> why the unnecessary switches? (CGA does mode switching in software,
> and enables simultaneous composite and RGB, hence the IBM vetsion
> dorsn't need switches)

I think that the switches mostly relate to output configurations; that
is, they don't change the basic operation.  For example, the "monochrome
composite" is probably  just luminance, blank and sync (VBS), whereas
the "color composite" is the complete CVBS signal.

I suspect that setting either of the two composite modes probably
disables the output at the DE-9.

It would be interesting to see what other combinations of switches
produce something useful.

Of course, this is all wild-hare speculation on my part, as I don't have
anything like this card sitting in my hellbox.


More information about the cctalk mailing list