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

Thu Aug 30 01:30:37 EDT 2012

Gil,

The serial drivers for the UART on the X-Port support 5 to 8 bit codes, but the driver (and the Linux serial subsystem) doesn't support 45.45 baud. Fortunately, the UART in the X-Port is quite flexible, and it can be configured to talk at 45.45 baud with very little work.

I have the ITA2<->ASCII 90% complete, but if you have something that is 'ready to ship', that would be handy too. In digging around my archives, I have complete conversion code that I wrote for a project that created a streaming audio steam of an RTTY feed generated from a text file -- a 'virtual ITTY'.

I think we could very quickly come up with a workable solution, using your hardware, with an X-Port and my software in place of the computer. I have schematics drawn up, and all the parts purchased to roll my own, but to be honest, I trust your design more than my own!

The X-Port can run a small web server to allow for configuration of the serial port. Once the serial port is up and running, I imagine that a very simple command line interface could exist (accessed via TTY) to allow for connection a TTYoIP server, or for direct connection to another TTY using the same kind of hardware. A fox generator could also be accessed via the same menu. In my vision, a TTYoIP server could be accessed that would give access to multiple channels -- 'chat rooms' (virtual loops), private person-to-person conferences, and read only streaming news services. Once connected to a server, the possibilities would be endless.

Thinking this through, I could use my streaming RTTY server to eavesdrop on the public areas and re-broadcast them as streaming audio feeds, for those so inclined...

I'll take some time to scrounge up my notes and get myself re-aclimated with what I've done so far...

- Keelan

On 2012-08-29, at 10:43 AM, <gil at baudot.net> <gil at baudot.net> wrote:

> 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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