[GreenKeys] Dovetron Connectivity...

[gil smith]

Hi Bill:

The "very simple hardware interface" to connect the dovetron 232 output to 
the pc is just a BNC-to-DB9 cable (I gave details in a greenkeys email a 
few days ago).

As for a pc (or dovetron) driving a current loop, I just happen to have a 
board that does that:
http://www.vauxelectronics.com/gil/tty-connect/

My first board is now running, software is half-finished, and I'm almost 
ready for a production run.  The PC interface does NOT need to output 
tty-speed baudot -- it is simply an ascii (8/1/n) port, running at 38400 
baud, using xon/xoff flow control.  A micro on my board converts to baudot 
at the desired speed for any of the three tty loops or the TU port.  Among 
other stuff.

What I'd like to see you and/or Buzbee do to your programs, is support my 
38400 port, and the configuration commands that I am implementing in 
TTY-CONNECT.

Also, I would like you and/or Buzbee to implement a "buffered-loop-through" 
mode, which I can use for speed conversion of two tty loops (eg: one tty 
loop at 100wpm and another at 60 wpm, or, the dovetron port at 75 wpm to 
drive a tty at 60 wpm).  For low-to-high-speed conversion, there is no 
problem, of course.  For high-to-low-speed conversion, a buffer is 
needed.  I have a small buffer designed into the board, but I realized that 
the pc can provide an enormous buffer with its standard buffered serial 
routines (and my code for this part is already done).  In other words, your 
program goes into a mode where I feed your 232 port the data from the 
high-speed tty, and you simply turn it around and send it back out the 232 
port to me (and, optionally, display it in a window).  To your program, it 
is again just a simple 38400 ascii port, but in a special mode where you 
just echo the incoming chars back out (getchar/putchar) -- BUT, with 
xon/xoff and tx buffering enabled on your port, I can throttle the data and 
drive the low-speed tty.

I have taken the baudot problem out of the pc program (a real pain under 
xp, I understand), and made the interface a simple ascii port.  Heck, now 
you can use the generic serial driver under windows, and print to your tty 
from a program like Word.  If you guys can tweak your tty programs to add a 
few features for TTY-CONNECT, we will all be able to do anything we want 
with our machines.

gil


At 08:46 PM 2/27/2004, William Bytheway wrote:
>Now that the Dovetrons are reaching all of us in measurable numbers, it
>would be neat if we could hear some success stories on how they are working
>"on-the-air".  Most of the units are Tempest with BNC connectors on the
>back, compatible with RS-232 voltage levels.
>
>Here is my idea:
>
>What we need now is a very simple hardware interface (HW) that allows us to
>connect the Dovetron to a PC (RS232) and a 60ma current-loop driver for a
>teletype machine.  The simplest design only uses three-legged transistors
>(EBC) and a single sided PC board.
>
>RTTYArt software was originally designed to transfer paper tapes to an ASCII
>file using a TD and TU capable of interfacing to a PC via RS232.  It had a
>limited graphic display capability customized to this purpose.  It also was
>capable of transmitting and receiving data via a TU with a PC interface.
>RTTYArt was not intended to be used as a terminal program, but it could be
>modified.
>
>The free offer:
>
>I will be willing to offer my RTTYArt MS Visual Studio 6.0 C++ source code
>free to those wishing to develop it into a full-blown RTTY terminal
>application capable of driving both a PC and a 60ma current-loop BAUDOT
>teletype machine (HW interface required).  Source code would be released
>under GNU GPL (i.e. free with restrictions).  Properly implemented, Heavy
>Metal and other capabilities could also be incorporated into the product
>(and vice-versa).
>
>Comments? Check out http://www.rtty.com/development/software/index.html
>
>73,
>Bill Bytheway
>K7TTY
>http://www.rtty.com/bytheway
>
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>GreenKeys@mailman.qth.net
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