[GreenKeys] iTTY and the Volpe USB Interface Board

[Paul Birkel]

Thanks Steve; I was working from
https://teletype.net/display/TEL/Volpe+USB+Interface+Board (and then
https://teletype.net/pages/viewpage.action?pageId=1277955) which I took to
be definitive, does list three manufacturing runs, and definitely makes
clear that no demodulation capability is included.  It’s up to software to
get from the iTTY stream to a character stream on USB.  So I was looking for
a software-based solution to bridge that gap.

 

Mike Douglas mentioned in a thread ~2 weeks ago that he was planning to
include a demodulator function in his project.

 

I see from your thread last month (“XR2211 demodulator circuit boards?”)
that you’re using the XR2211 in your respin, rather than the original
NJM2211.  I have a small stash of those that I acquired from utsource
(pretty reputable folks) three years ago  for this eventual purpose.  I
didn’t realize that this circuit was *also* referred to as “the Volpe
board”.  Oops.

 

So do mark me as _very interested_, thank you :->.  (Yes, I have outstanding
honey-do’s as well.)

 

In the meantime, has anyone set up a simple mechanism on Windows to read a
stream of characters from a file and feed the Volpe USB Interface Board?
That would be sufficient to meet my immediate stimulate-and-test the M19
objective.  Sounds like a Unix pipe to me 
 so Ubuntu running on WSL
(Windows Subsystem for Linux) with Win10 seems like a doable do.  But
perhaps I’m being naïve here!

 

From: Steve Garrison [mailto:steve.n4tty at gmail.com] 
Sent: Sunday, February 07, 2021 9:02 AM
To: 'Paul Birkel'; greenkeys at mailman.qth.net
Subject: RE: [GreenKeys] iTTY and the Volpe USB Interface Board

 

Paul, there are at least two different boards that might be being referenced
when you hear/see Volpe board.  The one you seem to be referencing here is
the one that allows you to connect your loop to your computer via a USB
port.  I’ve heard this board referred to as the Version 2 board.

 

The board that has been referred to as Version 1 is the board that I think
you would need to copy the ITTY streams.

 

I refer to that board as the Volpe Demod board.  It allows you to take the
audio from the ITTY stream and drive the loop to your TTY.  It requires
three connections.  A connection to an audio source, your PC audio out jack,
even the audio jack on my iPhone works, to deliver the ITTY tones to the
board.  Another connection for a 9 to 12V source of power.  And a final
connection to your loop.

 

I’m in the process of drawing up Eric’s original design of the Demod board
(aka Version 1) and producing the files to order some PCBs to build some of
these Demod boards, but have been side tracked by a honey-do list.  I hope
to get back to it soon and get some boards ordered.  The demodulator used on
the board is now obsolete, so it is no longer available through sources like
Digikey or Mouser.  I did order a few from China via eBay and they arrived
in Friday’s mail.  They have not been tried yet however.

 

Stay tuned if this is the route you would like to go.

 

And by the way, I’m not clear at all how the other items you mention might
accomplish the same goal.  Maybe others can enlighten us both.

 

Steve G./N4TTY

 

From: greenkeys-bounces at mailman.qth.net <greenkeys-bounces at mailman.qth.net>
On Behalf Of Paul Birkel
Sent: Sunday, February 7, 2021 6:38 AM
To: greenkeys at mailman.qth.net
Subject: [GreenKeys] iTTY and the Volpe USB Interface Board

 

Now that my M19 is approaching a working state (currently fussing with CAR
RET bounce/settling and the dashpot)  I’d like to exercise it from an iTTY
feed.

 

I have an assembled original (green PCB) Volpe USB interface board.

 

Is ttyBash ( <https://teletype.net/display/TEL/ttyBash>
https://teletype.net/display/TEL/ttyBash) coupled with fldigi (
<http://www.w1hkj.com/> http://www.w1hkj.com/) the standard/only software
path to connect-the-dots?  Any alternatives that I should be considering?

 

Does anyone have any specific experience establishing a feed from iTTY via
the Volpe board that they can share?

 

Thank you,

paul

 

 

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