(~$300), monitor (CGA had compoosite output, so could connect to cheap
CCTV, etc. monitors, and CGA even had a dedicated 4 pin Berg for the
SupRMod RF adapter), and maybe serial, and/or parallel.
On Tue, 31 Jan 2023, Ali wrote:
Fred,
This is the first time I am hearing about this. I always thought the connector
was for light pen input.
CGA had a DE-9 for video, (warning: incompatible with the DE9 MDP
connector, and incompatible with the bus mouse DE9)
plus an RCA for composite video,
plus a 4 pin Berg with composite video and power for an RF-modulator.
SupRMod was simply one of the most common after-market RF modulators that
used that 4 pin Berg.
1 12 volts
2 key
3 composite video
4 ground
(I am not sure whether "Berg" is the correct term for those connectors)
plus a 6 pin Berg for light pen,
1 light pen input
2 key
3 light pen switch
4 ground
5 5 volts
6 12 volts
IBM's manual for it: (with schematics)
https://minuszerodegrees.net/oa/OA%20-%20IBM%20Color%20Graphics%20Monitor%20Adapter%20(CGA).pdf
As far as I know, IBM did not offer an RF modulator nor a light pen.
after market was available.
The phosphor of the IBM monochrome monitor was too long a persistance for
light pen.
Compaq CGA and EGA boards ALSO had a mid-board 10 pin dual-row connector
for connecting to the Compaq portable internal monitor (12 pin but keyed)
EGA-Wonder had an add-on board for Compaq compatability.
Compaq boards were recognizable by the additional 90 degree bend at the
top of the board bracket, by a cutout in the bracket for access to the 4
pin Berg composite, and the connector for the internal monitor
https://oldcrap.org/2020/10/08/compaq-portable/
(I am not sure whether "Berg" is the correct term for those connectors)
--
Grumpy Ol' Fred [email protected]
