[GreenKeys] Smith Corona pc keyboard

[Henry Minsky]

At 10:28 AM 1/7/2003 -0700, you wrote:
>At 07:26 AM 1/7/03 -0500, you wrote:
> >I did a project once to convert a generic
> >PC kbrd scan codes to parallel ASCII using a microcontroller (Phillips
> >87C750) - it wouldn't be TOO awefully difficult to convert an ITA2 loop
> >to PC scan codes, plug your model 28 right into the keyboard port. I'm
> >sure Gil could do it if he wasn't busy making a PDP-8 ;))
>
>
>Hi Chuck:
>
>Ha, that does sound like it's up my alley.  Actually, I did write some code
>for a PIC micro to go into my TTY232 board.  Instead of the pc serial port
>needing to talk baudot at the correct speed, the PIC gets jumpered in
>between the 232 port and the tty loop.  It connects to the pc over a serial
>port at 19200 baud ascii, and converts ascii to/from baudot at whatever
>speed is needed.  Converting the tty chars to a higher speed for the pc is
>simple enough, but for slowing the pc data down to tty speeds the PIC
>relies on xon/xoff flow-control on the 232 port for (transparent) data
>throttling.  So the tty just looks like an ascii 232 device at 19200 baud.
>
>I suppose it would be easy enough to convert the tty chars to pc keyboard
>scan codes and feed it into the kb connector, but it would be a one-way
>hookup.
>
>However, all this talk lately about tty gears makes me wonder whether folks
>have a need for a gizmo to bridge two tty loops running at different
>speeds?  I actually need to make a speed converter for 232 ascii since I
>need to hook some slower-speed devices to higher-speed ports.
>
>It would easy enough to do tty-loop baudot speed conversion, to allow, say,
>a 100-wpm machine to connect to a 60-wpm machine.  Of course, there would
>no flow-control except an 80-char ram buffer in the pic, so dumping a
>100-wpm paper tape to the 60-wpm loop would overflow the buffer.  But
>typing on a 100-wpm keyboard would be fine.  And sending low-speed to the
>higher-speed loop, even a tape dump, would also be fine.  Anybody care?
>
>gil


I have thought about this problem ; I have a Model 28 geared at 100 WPM, but
I want a paper tape punch and reader, and they might be geared at
60 WPM, and it might be a pain to find 100 WPM gears. But I think the right
way to do this is to convert everything to a standard rs232 speed, say 19.2,
and the make converters that plug into that for 60 and 100 WPM.

You could have the thing speak software flow control as well.