[GreenKeys] Computer to teletype module...

[Wa3frp]

If anyone need the unit that John Nagle described here:


http://www.aetherltd.com/connecting.html


please let me know via email to wa3frp at arrl.net


I have this unit in a box and unused.  I bought it to convert my 
RTTY Art collection from paper tape to electronic format on my 
PC hard drive. (took hours)  But now that the job is done, 
the converter is unused. A shame to have it sit as it is very nice.


Price - shipping costs only. 


Russ - WA3FRP
wa3frp at aol.com

i-Telex 834328 WUTMPAM CHIL



-----Original Message-----
From: John Nagle <nagle at animats.com>
To: greenkeys <greenkeys at mailman.qth.net>
Sent: Sat, Feb 17, 2018 11:30 pm
Subject: Re: [GreenKeys] Computer to teletype module...

> From: Jordan Spencer Cunningham<js at cunni.co>
> Subject: Re: [GreenKeys] Computer to teletype module...
> Message-ID:
> 
> There are two major recent USB<-->TTY designs of which I am aware. There
> are likely more, but these are the two that are the best documented thus
> far. Neither is superior than the other; both have their uses and were
> designed with different approaches. Their creators are on this list and can
> speak more to this if they wish. Consider this a customer review of sorts.
> 
> The first I came across and the one I ended up building was designed by a
> fellow who shares your name, Eric Volpe. The interface is documented here:
> http://heepy.net/index.php/USB-teletype  While there was a run of these
> professionally made on a size-efficient PCB with SMD components around a
> couple of years ago I understand, that supply was depleted by the time I
> started asking around, so I ended up hand-assembling mine with through-hole
> equivalent parts and an Atmel32u2 dev board. 

    That's a nice little design. Does Baudot-ASCII translation, too.
Requires an external loop supply.

> The second I came across is also a great option, but I'm not nearly as
> familiar with it. It is John Nagle's recent design, documented here:
> https://github.com/John-Nagle/ttyloopdriver. It's similar in that it's also
> a USB/TTY interface, but its "current loop", if you will, is
> self-contained, meaning you can connect your machine right up to it without
> needing a current loop power supply. It's all powered from USB using a
> clever bit of engineering. From what I read on the GitHub readme for this
> design, its firmware does not perform ASCII translation (someone-- John or
> Steve-- correct me if this is wrong), but there is, of course, software
> that already exists like Heavy Metal that makes this easier to deal with.
> John also wrote baudotrss<https://github.com/John-Nagle/baudotrss>, which
> looks like it parses RSS feeds as well as sends/receives SMS. While you
> could probably find through-hole equivalents for the components used in
> this design, it's been designed strictly with SMD components. SMT is beyond
> my skill, nor do I wish to invest in the hardware that's really needed to
> do it right. It's definitely a good thing to learn if you want to truly get
> into modern electronics, though. This was the one main factor in why I
> decided not to use this design.
> 
> Either of the above designs could be professionally manufactured if hand
> soldering and figuring out through-hole equivalent components is not your
> thing. The problem I've found with this is that it requires a relatively
> large run to make the price per unit palatable, and I don't know that there
> is enough interest to have a large enough run done.

 Exactly, My design could easily be made by a PCB assembly shop,
but it's not an easy hobbyist project.

    There are no through-hole equivalents for many of the parts
in that design.  It has a specialized switching power supply which
uses modern switching power supply components. Those just aren't made
in through-hole. The layout around the switcher has to have very short
lead lengths or it won't work at all.  Having been forced to SMD,
I went as far as I could towards all SMD.  Once you're set up to
assemble SMD, it's easier to place SMD parts than through-hole parts.

    If there was a market for 100 of those things, it might be
worth having them manufactured.  Less than that, not worth it.

    I have an old, easy to build through-hole design at

http://www.aetherltd.com/connecting.html

which requires an external 120VDC power supply and an external
USB to serial converter.  I built and used several of those.
But surplus 120VDC power supplies are now hard to find.

				John Nagle
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