[GreenKeys] Xitex video terminal

[Chris Elmquist]

On Friday (01/01/2010 at 01:53PM -0600), Jack Rubin wrote:
> > A large board, a Zitex SCT--100 video display board was 
> > located in the upper portion of the unit, but had broken 
> > free of its mounts during shipping (or before), and was 
> > basically laying on the main board of the unit. By googling 
> > the board, I was able to identify it.
> > 
> > Now, is anyone familiar with this modification? Have any 
> > documentation? I suspect it was used to make the unit a 
> > standalone terminal with composite video display...
> > 
> > Does anyone have any more information?
> > 
> 
> Dave,
> 
> You've pretty much ID'ed it correctly - the Xitex board was an S100 video
> "terminal" with keyboard and video capabilities. It could be used with an
> S100 computer or was available as a standalone terminal. I have a unit
> mounted in a keyboard with a single edge connector for power along with an
> accompanying composite monitor. I've got docs somewhere if you get
> desparate.
> 
> Jack

I knew that name Xitex sounded familiar and sure enough, I just dug
through a very deep pile of documentation I inherited from the estate of
the late W0AUS and found there, the SCT-100 Single Card Video Terminal
manual.

So, I have one too if you get desperate.  There's about 50 double side
pages including a schematic.

oh-- and the receipt for it... The "full kit" cost $157.00 in March
1978 ;-)

Pretty cool unit.  Does baudot at 45.45 or 74.2 baud and ascii at 110 or
300 baud. It does both 20 and 60 mA current loop and RS232.  It can take
a parallel keyboard in and produces composite RS170 NTSC video coming out
at 16 lines x 64 characters.

All the secret sauce is in the MK3870 microcontroller though... including
the firmware in the aboard ROM...  so, here's hoping that puppy is still
amoung the living.  There's seven 21L02 SRAMs for the video frame buffer
and then a character generator ROM that produces the five pixel wide
characters.

Fun.

73, Chris N0JCF

-- 
Chris Elmquist