It is the same as the video Black sync used in TV studios to sync the cameras together.
It allows multiple adaptors/monitors to operate using a single retrace timing reference..
This removes the rolling caused when televising a room full of computer monitors
like you see on a news/weather set.
There are some other user like video overlay that were seldom used.
It can also be also used to allow mixing and switching between monitor outputs onto video
tape
or onto a split screen, without a time base corrector.
Bob
On Tue, 20 Dec 2005 23:53:56 -0500, Roy J. Tellason wrote:
On Tuesday 20 December 2005 11:45 pm, Jim Leonard
wrote:
> This is an original IBM CGA, not a clone.
Speaking of such, what are the RCA jacks (two of them)
on those cards for?
Is one of those supposed to be a composite output?
--
Member of the toughest, meanest, deadliest, most unrelenting -- and
ablest -- form of life in this section of space, a critter that can
be killed but can't be tamed. --Robert A. Heinlein, "The Puppet Masters"
-
Information is more dangerous than cannon to a society ruled by lies. --James
M Dakin