5150/5151 Video Card??

Fred Cisin cisin at xenosoft.com
Sun Aug 14 22:04:25 CDT 2016

On Sun, 14 Aug 2016, Adrian Stoness wrote:
> should work fine u got rca and vga on that card might not be colour but it
> should work


What card is that?

The IBM 5150 was the PC.

The IBM 5151 was the IBm green screen "Monochrome" monitor.  The card for 
that ("Monichrome Display and Printer Card"), and the various clone MDA 
cards, did NOT have RCA, and were NOT at composite video rates. 
(18.43?KHz horizontal, 50Hz? vertical)
It had a DE9 for the monichrome monitor and a DB25 for printer ("Cenronics 
compatible parallel")
Hercules' video card was an imitation of the MDP, with more RAM, and 
monochrome 720x350 graphics.

On the other hand, the CGA card did have RCA composite video (close to 
RS170), and "RGB" (DE9).   About 15.75KHz? 
It was NOT at the correct frequency for the 5151 monitor!

IBM did not even have sufficient protection in their circuits if you 
plugged a monitor into the wrong card, or set the video card to 
incompatible frequencies!

The IBM EGA card had TWO RCA jacks, but neither were composite output.

What is RCA and VGA??

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