8-bitters and multi-whatever

Roy J. Tellason rtellason at verizon.net
Mon Sep 10 15:12:00 CDT 2007

On Sunday 09 September 2007 23:23, Dave McGuire wrote:
> On Sep 7, 2007, at 11:49 PM, Roy J. Tellason wrote:
> > Unfortunately instead of RS232 Televideo has something else going
> > there (RS422?),  not easy to interface too,  and they distribute their
> > "network" out amongst what other Televideo boxes you have,  which in my
> > case is none.I guess with an S-100-based system you could always add more
> > cards,  and somehow or other make it work.
>    They were RS422 if memory serves.

Probably.  I never could keep those straight.  I remember reading up on it at 
the time and that it was some kind of differential-current interface,  and I 
might even have the datasheets for the chips they used,  though heaven only 
knows where I'd get one if I needed one (probably ask on this list :-).

>    I worked at a computer store when I was in high school, from 1984 to
> 1986...we used one of those > Televideo distributed CP/M-ish systems (810?)
> there, for store operations/POS/inventory stuff.  It worked very well and
> was reliable, but it wasn't very fast.  Our POS and inventory system was
> written in CBASIC-80.  It was good stuff.

The difficulty I see is that if I were to ever want to try and use one of 
those I'd have to find hardware that would talk to it.  Though I *did* get a 
hold of an ISA card with a boot rom that wanted to talk to that.  I haven't 
the assembly skills to do a dump of it and see what it's trying for,  but 
apparently it wants to load some file from the other end and of course isn't 
finding it.

I guess if I'm ever gonna do anything with that box I'm gonna have to find 
some more TeleVideo hardware.

Got a 40M _eight inch_ HD in it,  along with a tape drive,  I forget what kind 
but the book tells me that it stores a whopping 14MB.  :-)  The HD is 
belt-driven,  and that slipping was I think one of the difficulties I was 
having the last time I tried to boot the machine.  Don Maslin (sp?) sent me 
another belt,  but I never got around to putting it in there.

Too bad those aren't rs232 ports,  that box could be useful for some things 
even if I never went anywhere near the original application.

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

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