[GreenKeys] Feeding ITTY to the teletype; simulating M33/35 teletypes hooked to computers like in the 70s

Wed Aug 29 18:01:04 EDT 2012

RTTY.COM already has an ASCII telnet compatable interface for accessing the
data stream.  Data transmitted via BAUDOT at 45.45 baud via streaming audio
is echoed to the ports shown below.  In additon, the Autostart channel
allows two way real time conversations.  This feature has been operating for
several months.  The links below bring up a real-time JAVA applet
application that allows one to monitor activity.

For ITTY:
JAVA URL:  http://itty.rtty.com/chat-itty.html
TELNET Port: 693

For National:
JAVA URL:  http://national.rtty.com/chat-national.html
TELNET Port: 699

For Autostart:
JAVA URL:  http://autostart.rtty.com/chat-autostart.html
TELNET Port: 695

For the future Podium (not active yet):
JAVA URL:  http://podium.rtty.com/chat-podium.html
TELNET Port: 697

  _____  

From: gil at baudot.net [mailto:gil at baudot.net] 
Sent: Wednesday, August 29, 2012 10:43 AM
To: Keelan Lightfoot; Paul Heller
Cc: George B. Hutchison; aaa-greenkeys; William Bytheway
Subject: RE: [GreenKeys] Feeding ITTY to the teletype; simulating M33/35
teletypes hooked to computers like in the 70s

Hi Keelan:

Interesting idea.  I have wanted to have an ethernet-to-tty adapter for some
time.  I used x-ports years back, but didn't write any code for them -- just
put them into a custom product for an oem customer.  I am looking into a
similar can from Digi for a new project.  The nice thing about either the
lantronix or digi parts is it is just a simple little small-footprint can,
has enough compute power to do lots internally, and only costs about $50 to
$60 qty 1.  Just gotta program the can, and then you need some sort of
pc/mac/linux client to discover and connect to it, or maybe something
browser/java-based or whatever.

The nice thing about George and Bill's ITTY, is that you can take the audio
out of a PC sound card, feed it into your vintage dovetron, and plug your
tty into the loop jack.  Very cool, and simple.

Decoding the audio with an FFT cruncher, while a fun project in itself,
seems like a big task just to get at the data the George and Bill are
pumping into their modulator.  I would imagine it would not be difficult to
get the ITTY simple baudot/ascii text available on the internet as some sort
of data stream (George? Bill?)

I did the tty-connect 232-to-loop stuff years ago, and always meant to
update it, but never found the time.  I considered making it a usb-to-loop
converter, to get around all the problems with obsolete serial ports on pcs,
but ethernet would be better.  Even better when the code can be embedded in
a can.  So a couple of things come to mind:

1)  Is it necessary to demodulate the audio from itty, of can we get that as
an internet data stream somehow?
     - a question for George and Bill

2)  Whether getting the data directly, or demodulating the audio, gives you
a stream that you can feed to a serial port for a tty loop.  
     - sounds like you can do this code in the can, along with all the
mystical internet things that are needed.

3)  The stream should be in ascii, so we can send it to an M33/35/43 machine
at 110-baud, or subsequently converted to baudot (with inserted figs shifts
etc) for all the rest of our machines.
    - I wrote code for this years ago.

4)  The serial port will be a logic-level (3.3V or 5V) signal that needs to
go to an opto-isolated loop keyer.
    - I have done this before.

Hmm, sounds to me like if you get the code to get data out of the can, I
could modify my tty-connect board to rip out the little 232-pic-converter
section, drop in your can, and provide the loop interfacing.  If you
additionally provide, on one of the gpio lines, a machine-power signal, a
couple of seconds before sending data, we could automatically power the tty
too.

Then we need some way to, using a browser maybe, send the itty feed to our
machine at address X.  Or maybe send a text file to someone else's machine
at address Y.  Maybe be able to send an email to a machine.  Or maybe use
twitter from a cell phone to send a message somewhere on someone's machine
(like the guys at dangerous prototypes did with a thermal printer).  And a
way to toggle our machine into private/public mode.  And a pushbutton to
print out a pre-loaded message as a quick demo for when people come to
visit.

A whole stinkin' network of teletype machines, using the internet like
telex, er, telexnet?

I'm just rambling now, but there there might be a not-too-difficult project
there.

gil smith
greenkeys moderator
gil at baudot.net
www.baudot.net
Vaux Electronics: 480-354-5556

-------- Original Message --------
Subject: Re: [GreenKeys] Feeding ITTY to the teletype; simulating
M33/35 teletypes hooked to computers like in the 70s
From: Keelan Lightfoot <keelan at grenander.com>
Date: Tue, August 28, 2012 9:45 pm
To: Paul Heller <paul0926 at comcast.net>
Cc: Greenkeys <greenkeys at mailman.qth.net>

Paul,

I've started work on a similar project, but my idea is to cut out the audio
middle man. I've written a server in C that handles communication between
multiple TTYs over IP, using a ring buffer clocked at 45.45 baud to allow
for semi-realistic garble when more than one person is talking at a time.
For hardware, I'm using a Lantronix X-Port, which runs Linux. It has a
single ethernet port, a serial port and a couple general purpose IO pins.

I've tweaked the linux kernel on the X-Port to allow me to reduce the baud
rate of the serial port to 45.45 baud, I just need to write the client
software.

I've got all the bits and pieces accumulated to build a prototype board with
a loop keyer, patiently waiting until my interest cycle swings that way
again.

- Keelan

On 2012-08-28, at 7:55 PM, Paul Heller wrote:

> I'm experimenting with something, but it is very early days. There are
small computers, the size of an Altoids (the mints) tin. These full fledges
computers run linux...

- snip -

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