[Color Computer] [coco] software modem for OS-9

[James Diffendaffer]

Actually, I think there is a design for this type of RS232 interface
in one of the old TRS80 Magazines (80 US Journal or 80 Micro? Not sure
what issue).  The parts appear to adjust the analog signal levels but
nothing else so the parts *should* be available and cheap.  Since it
deals with analog signals and the Model 1 and CoCo both interface to
the same tape drives the circuit should work.  It would probably work
with any similar tape interface for that matter.

That doesn't eliminate the problems with bit banger ports and OS-9.  
 The timing loops are a PITA and VERY sensitive to any code changes. 
Interrupts have to be disabled and a task switch would really break it.

If I remember right a "Kansas City Interface" is just a tape interface
and is *similar* to what is already in the computer.  I think it goes
goes from RS232 to tape but I haven't read about that in years.

--- In ColorComputer at yahoogroups.com, "Stephen H. Fischer"
<SFischer1 at M...> wrote:
> Hi,
> 
> What you want is something called, if I remember correctly, a
"Kansas City
> Interface".
> 
> I have one and the artwork for a circuit board. Documentation and
perhaps
> even a spare board and some parts. I am not sure if a RS232 or a current
> loop was used, I may have both on my board. Parts may be hard to
come by 
> today.
> 
> Basically a 300 Baud modem tone generator and tone receiver that was
used to
> record on audio tape.
> 
> 
> > On Thursday 07 July 2005 21:05, George Ramsower wrote:
> >> I can't imagine why anyone would want to do this, but I'm curious
> >> if someone ever wrote a routine for OS-9 that will use the cassette
> >> port to communicate with a device using modem tones A.K.A. FSK...
> >> like is used to utilize the cassette in RSDOS.
> 
> >> If there isn't a driver for this, perhaps someone has an old
> >> acoustical modem they might wish to part with. I can modify it for
> >> this application, using hardware to do the work which could be done
> >> in software, but I don't know how to program in assembly..
> 
> I may have one of these also, for sure the acoustical part.
> 
> 
> -- 
> Stephen H. Fischer




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