[GreenKeys] TTY loop interface

Wed Aug 11 14:16:43 EDT 2021

Chuck, 

I was more or less in your position six years ago. Now I have a barn more or less full of these machines and am still on the lookout for more. Be careful. Once it takes hold of us, it never lets go <http://www.theargonath.cc/characters/gollum/sounds/never.wav>.

Back when I finally got my first machine (an AN/UGC-74B for which I vastly overpaid), I was thinking of various ways I might be able to build an interface and communicate across the interwebs. After researching what was already out there, I eventually came to the conclusion there's no need to reinvent the wheel when it comes to loop interfaces. There are several solutions that would probably already meet the requirements of what you're hoping to do to one degree or another, at least from what I understand you're trying to do. Of course, another solution isn't a bad thing, either.

It sounds like the main thing you're hoping to do is have a small device that can remotely control another teleprinter using your local machine across the internet or even a POTS or VOIP line.

1. i-Telex -- pretty much a turnkey solution for what you describe. Has onboard networking, so you don't have to connect it to another device outside a network switch able to route to the internet. Developed with European style Telex system machines in mind, but you can request one with a current loop interface on it so that most American style machines from any era will be compatible as well (if I recall correctly, you'll need a separate power source for the current loop). You have a number assigned to you, your buddy has a number assigned to him, and whenever you wish to exchange comms, one of you "dials" the other. Whatever's typed on one machine is printed on the other. The person on the receiving end doesn't even have to be there waiting to answer. Pretty cool setup and network these guys have developed. The hardware's a little pricey, but I think the investment is well worth it. I haven't yet joined the club, but it'll be happening soon as I can get the barn interior finished and organized to a useful state. Translated page with information and contact buttons here <https://translate.google.com/translate?sl=auto&tl=en&u=https://www.i-telex.net/hardware/>. 

2. Nagle board -- previously mentioned, a cool little board. I don't have one, but I borrowed one from a fellow GreenKeyer some time ago, and it's pretty slick-- biggest thing standing out for this board in my view is that it powers the loop completely off of USB, which is really cool. Biggest problem is it's fairly expensive to build even in bulk due to some of the components, and John's mentioned that there are components that aren't being manufactured anymore, adding further complexity. Now, just because this is a USB interface and doesn't have an ethernet port doesn't mean it can't fit your needs. Read on for why.

3. Volpe board -- not sure if anyone's mentioned this one yet. It's what I use almost exclusively. Similar to the Nagle board, but it doesn't power the loop (you need an external power source), and it is equipped with onboard USTTY <--> ASCII translation among a few other neat firmware tricks. It's always been able to be manufactured or even hand-assembled for less than $50 each, but I'm unsure what that would look like now with the chip and general supply lines all out of balance. I am not smart enough to design anything like this, but I did a manufacturing run of 100 a couple years ago and wrote up some docs <https://teletype.net/display/TEL/Volpe+USB+Interface+Board> that may be helpful. I know I have a handful left, but I also have a handful of requests from people who wanted some that I'm in the process of catching up on, so I don't know if I actually have any to spare. Still, let me know if you're interested off-list and I'll see what I can do once I fulfill these other requests. CuriousMarc actually ordered one from me, though what he's using on his videos is something of his own make, I believe. I have been wanting to do another run of 100 or more, just don't have time right now. This board also does not have built-in networking, but again, that's not necessary to do what I understand you're trying to do. Keep reading for why.

4. There are others not as popular amongst GreenKeyers, but I know I've seen at least one or two other recent USB <--> current loop designs around the web. There are always the various old RS-232 <--> current loop designs, but when you can use a USB device, the RS-232 stuff just adds more complexity unless the purpose is to specifically use old hardware for the sake of using old hardware, which is a valid way for a nerd to have fun, by all means.

If you connect one of the USB <--> TTY boards to a Raspberry Pi, you have all the hardware you need to communicate with someone else on the interwebs in a small package; you just need some software to handle the network comms. I've been slowly writing a suite of scripts to interface my machines with email, SMS, RSS, and various other protocols including raw TCP, meaning you could have two teletypes using USB <--> TTY boards connected to the internet communicating bidirectionally in realtime via a TCP connection. 

Eric Volpe (the creator of the Volpe board) wrote a suite of Python scripts <https://github.com/epvuc/loop-gateway> to do similar things including a working, bidirectional TCP communicator. At least I assume it's working-- I haven't personally tested it. But in theory his software alone plus a Volpe board, power supply, and Raspberry Pi is all you need to do what you describe.

My TCP communicator I got working briefly a while back between two teletypes, but I haven't had time to really work on it since, and I haven't gotten it to work again since-- clearly lots of bugs to work out. It's not fit for human consumption by a long shot. I am looking forward to it, though-- the suite I'm writing leverages a Raspberry Pi's GPIO pins to control relays and automagically turn current loop and teletype motors on/off when an incoming message (email, SMS, RSS, TCP, whatever) is detected or button is pushed. Fully automated motor control/autostart, as it were.

Anyway, the point of all this is that it's entirely possible to do what you're hoping for with a USB <--> TTY board and some software-- you don't necessarily need to have a dedicated device with built-in RJ45 and TCP/IP stack. I prefer a plain old USB plus computer option over a dedicated, networked board because software controlling the board via a generic computer is more versatile whilst dedicated hardware is less so. If you build a hardware device specifically for communicating over the interwebs, that's cool, but you're limited by the hardware and wouldn't be able to expand functionality as much or as easily should you decide you want to experiment with other protocols/technologies. I suppose if you built the hardware with a powerful enough SoC (i.e. excess of memory and processing power) and potentially other I/O options, you would have more versatility to add functionality to the firmware later. It's still easier to expand functionality on a generic system, though.

Anyway, maybe this is more than you bargained for, but hopefully some helpful ideas.

-
Jordan Spencer Cunningham
teletype.net | GreenKeys Search Engine: teletype.net/gksearch
SMS via teletype: 385-308-4898 | Email via teletype: tty at nerdology.org

On Wed, Aug 11, 2021, at 8:36 AM, Chuck Robertson wrote:
> Steve, etch? Wire wrapping tool?
> 
> Here are my thoughts. I'm still in the green stages. I've yet to acquire a teletype machine, send or no send, so not to worry yet. One step at a time.
> 
> After I find a machine or two and get them working, I have really limited experience and understanding of assembling electronics, so I think the best way I can solve the interface problem is by finding someone who does and then spending the lion's share of the time I would have spent building it generating funds for the project. It shouldn't be too hard. MIT is right across the river.
> 
> However, I'm decent with a soldering gun, so if this person built one, or if I had one to look at, I might be able to copy it, and if I can make one, I can make several. Then my writing partner in Seattle could have one, and anybody else on GreenKeys who wanted one could have one too.
> 
> I'm also trying to imagine the best outcome. John Nagle's documentation is impressive to this newbie, but for me, it actually wouldn't be a single USB input, it'd be a USB input and an RJ-45 jack and controller so I could plug it into a local network, like a printer or print server, and print to it remotely. Then my writing partner could print to mine, and vice versa. I don't know if anyone else would find that useful, but that would be a powerful use case for us.
> 
> If I'm making this too complicated or have a glaring assumption that's going to trip me up later, please let me have it! (Remember, I don't even have a machine to study yet.)
> 
> Thanks for all your help.
> 
> Chuck
> 
> On Wed, Aug 11, 2021 at 8:19 AM steve bennett <raleigh_ranger at yahoo.com> wrote:
>> 
>> Chuck,
>> 
>>   No I do not.
>> On a side note these drivers work on both directions.
>> If your teletype is read only (no keyboard) you do not need to build all of it.
>> You can leave out the parts for sending.
>> I would not bother with trying to etch a circuit board. Just use a wire wrapping tool.
>> Easier than soldering and easy to correct mistakes.
>> 
>> -Steve
>> 
>> On Tuesday, August 10, 2021, 09:19:24 PM EDT, Chuck Robertson <hootsk at gmail.com> wrote:
>> 
>> 
>> Steve, do you know anyone who's built John Nagle's ttyloopdriver?
>> 
>> Besides John Nagle, I suppose.
>> 
>> Chuck
>> 
>> On Fri, Aug 6, 2021 at 10:20 PM steve bennett <raleigh_ranger at yahoo.com> wrote:
>>> 
>>> Chuck,
>>> 
>>>   When you eventually get around to building an interface box, this might be a good one to look at.
>>> I have not been down this road yet so others may have better input.
>>> 
>>> GitHub - John-Nagle/ttyloopdriver: Hardware device for driving antique Teletype machines <https://github.com/John-Nagle/ttyloopdriver>
>>> 
>>> 
>>> 
>>> 
>>> GitHub - John-Nagle/ttyloopdriver: Hardware device for driving antique T...
>>> 
>>> Hardware device for driving antique Teletype machines - GitHub - John-Nagle/ttyloopdriver: Hardware device for d...
>>> 
>>> 
>>> 
>>> 
>>> 
>>> 
>>> On Friday, August 6, 2021, 04:14:27 PM EDT, Chuck Robertson <hootsk at gmail.com> wrote:
>>> 
>>> 
>>> Steve,
>>> 
>>> I try to only tackle one problem at a time to avoid getting overwhelmed, and right now that's still locating a couple of working teletype machines or machines that could be made to work — one for Newton, Mass. and one for Seattle.
>>> 
>>> But last night I was watching the channel of the YouTuber called CuriousMarc and wondered if he's published schematics or instructions anywhere. I'm sure you've seen his videos. You can see the hardware he's used to connect his teletypes to a Linux PC. I'm not an engineer, but I'm capable of following plans, wiring and soldering, and persistent. Were I able to build one, I could build three.
>>> 
>>> This is one of the many times when I wish my Dad were still alive. He was a brilliant MIT-trained electrical engineer and excelled at crushing these sorts of hacks. He died of cancer in 2018.
>>> 
>>> Chuck
>>> 
>>> On Fri, Aug 6, 2021 at 10:33 AM steve bennett <raleigh_ranger at yahoo.com> wrote:
>>>> 
>>>> Chuck,
>>>> 
>>>>   Have you had any luck finding plans for an interface between the Mac and the TTY?
>>>> I might want to take that route at some point so I am curious what you come up with.
>>>> Someone on here posted a wiring diagram showing how to use a polar relay to connect to
>>>> RS232 but I don't know how you would deal with the baud rate and ascii to baudot conversion.
>>>> 
>>>> -Steve
>>>> 
>>>> On Thursday, August 5, 2021, 01:11:48 PM EDT, Chuck Robertson <hootsk at gmail.com> wrote:
>>>> 
>>>> 
>>>> Steve, an expert behind a screwdriver sounds great to me. The further along a machine is toward tuned, probably the better chance I have of success (and staying on this list!).
>>>> 
>>>> Also thanks to James and everyone else who's offered assistance. No reply yet from the Craigslist ad for the UPI RO in Metuchen, NJ.
>>>> 
>>>> Before, I mentioned my impetus is that I have a kind of writing partnership with another writer in Seattle. (I work for a TV network, but he's an actual professional writer, for places like Disney and Pixar.) We work on episodic scripts together either in cloud apps or sending them back and forth by email (so far unsuccessfully, but in scriptworld things can change quickly). This has been complicated recently because he's discovered his grandfather's typewriter, loves it, and believes its more cumbersome nature slows him down, to his work's benefit. He believes the moments of extra time he spends waiting or pressing keys, he also spends thinking, and it's actually improved his writing. (It might be true.) He's been encouraging me to try this, but I'm not ready to give up screens and software, and when I told him instead of getting a typewriter, I was going to try to set up a teletype to type out my scripts, he was like, what's a teletype? 
>>>> 
>>>> Originally I thought I'd output from the Mac laptop to the teletype and mail him the pages or roll. But then I thought, what if we each had a teletype, and I transmitted the script over the net to it instead? I could call him and tell him to turn the machine on, and it'd type the script out at his house instead. He could watch it come through a character at a time if he liked. And when he finished one, vice versa.
>>>> 
>>>> Chuck Robertson
>>>> Newton, Mass.
>>>> 
>>>> On Wed, Aug 4, 2021 at 6:07 PM steve bennett <raleigh_ranger at yahoo.com> wrote:
>>>>> 
>>>>> Chuck,
>>>>> 
>>>>>   I am holding on to your contact information because I have an Associated Press M15 RO
>>>>> I might let go after I get it working.
>>>>> I have since acquired a M19 so I do not need both.
>>>>> I will keep you in mind. I paid $50 for it and bought parts. I would rather sell it as a working unit
>>>>> rather than a basket case. Stay tuned.
>>>>> 
>>>>> -Steve AD8CI
>>>>> 
>>>>> On Wednesday, August 4, 2021, 12:37:56 PM EDT, Chuck Robertson <hootsk at gmail.com> wrote:
>>>>> 
>>>>> 
>>>>> Hello GreenKeys,
>>>>> 
>>>>> Is the person who posted this UPI machine on Craigslist on this list? Or does anyone on this list know this person?
>>>>> 
>>>>> https://cnj.craigslist.org/zip/d/metuchen-vintage-upi-teletype-machine/7349823306.html
>>>>> 
>>>>> I've sent a couple of emails, but so far, crickets. If you're them, please call me, or if you do, please let me know or just give them my number. I haven't found a teletype yet and I'm really champing at the bit to get started.
>>>>> 
>>>>> Thanks,
>>>>> Chuck Robertson
>>>>> Newton, Mass.
>>>>> (206) 579-0321
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>>>>> 
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