[GreenKeys] Xitex video terminal/CW Decoder

[Chris Elmquist]

yes! In the same folder with the SCT-100 manual is a manual for the
ABM-200 which was apparently a board that was used in the MRS-100
"Morse Transceiver".

This ABM-200 used two MK3870 microcontrollers to convert from baudot/ascii
to morse and from morse to baudot/ascii.  The two micros were then connected
back to back such that you could come in with baudot, convert to morse
and then go out with ascii... and vise-versa.  There is a long discussion
about the throughput and how it is based on the variable length of the
morse characters.

There's a chart that shows the conversion from baudot/ascii to morse
and even the special morse characters you mention.

LF	=>	....._

CR	=>	_._..

BEL	=>	._._.

and numerous others.

Pretty impressive stuff for 1978.  These guys must have really loved that
MK3870 micro.  Maybe one of them worked for Mostek ;-)  The device had a
mask-programmed ROM so you had to order them pre-programmed from Mostek.
That meant doing all of your development and debug on a development system
probably purchased from Mostek.  Not cheap stuff in those days.  So they
must have been doing a pretty good business with these terminal units.

Chris N0JCF

On Friday (01/01/2010 at 11:28PM +0000), K0BX wrote:
> I had a Xitex video board for a while, it worked well.
> 
> But the thing that I had from Xitex was a CW Decoder.  It had a 28 
> character buffer with a two digit readout to tell you how much buffer 
> was available.
> What made this decoder unique was that it would output in 5 level baudot 
> and key a 60 mil loop.
> 
> So I was sending and receiving CW with my model 28ASR!!  I built it from 
> a kit and it worked very well.  The Xitex people even had a special 
> baudot mode where the CR/LF's and other control characters had their own 
> unique CW character.
> That way if two of them were chatting on the air, you could even decode 
> the CW cr/lf's.
> 
> Of course this Decoder would also output in ASCII and drive their Video 
> terminal or any other video terminal.
> 
> I wonder if anyone remember this decoder??
> 
> Joe K0BX
> 
> Dino Papas wrote:
> 
> >Believe it or not I actually have one of these sitting in the closet as well.  Now here's the cool (or dumb as the case may be) story.....I built this thing up and used it for a short time on RTTY before building a RTTY I/O for my Apple II.  I then sold the Xitex box I'd built at a hamfest....several years later at another hamfest what did i run across?  You guessed it, a guy selling my box....I just had to have it back!  So, there it sits in the closet waiting for a day when I need a retro project to work on.
> >
> >Dino KL0S
> >
> >On 1Jan2010, at 6:09 PM, Chris Elmquist wrote:
> >
> >  
> >
> >>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?
> >>>>        
> >>>>
> >
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-- 
Chris Elmquist