22 Dec
2005
22 Dec
'05
12:43 a.m.
On Tuesday 20 December 2005 11:45 pm, Jim Leonard wrote:
The IBM CGA card has one RCA socket (in the UK, we called it a 'phono
socket', BTW). It is composite NTSC video. Stnadard signal level, etc.
The IBM EGA card has 2 such sockets. Both are essentially unconnected.
The outers are connected to logic ground, the inners go to pins on the
'feature connector' only. I actually added a little daughterboard to an
EGA card years ago (a couple of TTL chips, a few discretes) to make
composite mono video available on one of the RCA sockets, to drive a
greenscreen composite monitor. Remember that the EGA card can do US TV
(==CGA) rates.
-tony
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?