[GreenKeys] Affordable current loop adapter

Sun May 18 12:56:43 EDT 2025

Hate to jump in but i would love to have an “idiots guide” for doing this for an 28ASR.

Unfortunately my stuff is all in storage while we move…. But we are coming back soon!

> On May 18, 2025, at 11:23, John, W9DDD <w9ddd at tapr.org> wrote:
> 
> So out of curiosity, did the board get modified to match the special configuration of the wall mount 28KSR or was the 28 wiring  modified to match the board, or both?
> 
> Which reminds me, Jeffrey are there any special items in the LESU, like a selector magnet driver or line relay?
> 
> 
>> On 5/18/2025 9:12 AM, David Stickelman wrote:
>> Having used this interface it works reliably with minor modifications on an M28.  It was fairly straightforward to build but you will have to get components from Mouser or similar.  I use Terra term to send text to regulate the rate characters are sent for large blocks of text.  It ends up being the size of a pack of cigarettes.
>> 
>> http://stickelman.net/index.php/2025/02/23/getting-started-with-a-teletype-my-consolidated-notes-on-restoration/
>> 
>> http://stickelman.net/index.php/2025/01/07/things-for-your-teleprinter-to-print-and-the-significance-of-ryry-in-teletype-baudot/
>> 
>> Mobile
>> 
>>>> On May 18, 2025, at 8:24 AM, Mike Douglas via GreenKeys <greenkeys at mailman.qth.net> wrote:
>>> 
>>>  Here’s the 5-bit 60ma version from DeRamp. The selector magnet loop of a 28 can typically be wired to be compatible with this adapter. It can also be configured to run at 60 or 100 wpm depending on how your 28 is geared.
>>> 
>>> Model 15 Interface <https://deramp.com/model15_interface.html>
>>> deramp.com <https://deramp.com/model15_interface.html>
>>>    
>>> <computer-turned-on-32-288937-32x32-1.png>
>>> <https://deramp.com/model15_interface.html>
>>> 
>>> 
>>> 
>>> Mike
>>> 
>>>> On May 18, 2025, at 2:21 AM, Erik Grant <nitewolf1138 at hotmail.com> wrote:
>>>> 
>>>> 
>>>> While this one is for the M33, it might be worth while to contact this guy @ https://deramp.com/tty_adapter.html <https://deramp.com/tty_adapter.html>
>>>> Teletype RS-232 Adapter - DeRamp.com <https://deramp.com/tty_adapter.html>
>>>> The Teletype RS-232 adapter comes fully assembled and tested as shown in the pictures on this page. A telephone cord and modular DB-25 connector are not included.Version "B" of the board is now shipping.
>>>> deramp.com
>>>> 
>>>> 
>>>> ~KF7WAI
>>>> 
>>>> ------------------------------------------------------------------------
>>>> *From:* greenkeys-bounces at mailman.qth.net <greenkeys-bounces at mailman.qth.net> on behalf of Tim McNerney <mc at media.mit.edu>
>>>> *Sent:* Thursday, May 8, 2025 9:52 AM
>>>> *To:* greenkeys at mailman.qth.net <greenkeys at mailman.qth.net>
>>>> *Subject:* [GreenKeys] Affordable current loop adapter
>>>> I need to test my 28RO.
>>>> Most of the RS-232 to 20 mA current-loop adapters are "wicked expensive."
>>>> Plus nowadays, RS-232 is not exactly easy to find as an interface.
>>>> So I'll be up to $200 before I finally connect to a computer via USB.
>>>> And of course USB to current-loop... good luck finding that adapter...
>>>> 
>>>> Can anyone recommend a circuit for a simple 20 mA current loop transmitter?
>>>> I have EE and soldering chops.  Happy to build my own prototype.
>>>> 
>>>> BTW, I've noticed lots of affordable 4-20 mA current loop transmitters
>>>> for remote industrial sensors.
>>>> Can these be adapted to serve as a 20 mA digital transmitter?
>>>> Intuition makes me think yes, but I want to double-check.
>>>> Maybe 4 mA does not equal "0".
>>>> 
>>>> Thanks.
>>>> --Tim McNerney
>>>> 
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>>>> 
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>>>>>> Jordan Spencer Cunningham's GreenKeys Search Tool: https://teletype.net/gksearch
>>>>>> 2002-to-present greenkeys archive: http://mailman.qth.net/pipermail/greenkeys/
>>>>>> 1998-to-2001 greenkeys archive: http://mailman.qth.net/archive/greenkeys/greenkeys.html
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>>> 
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>> 
>> 
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>> 
>>>>> Jordan Spencer Cunningham's GreenKeys Search Tool: https://teletype.net/gksearch
>>>>> 2002-to-present greenkeys archive: http://mailman.qth.net/pipermail/greenkeys/
>>>>> 1998-to-2001 greenkeys archive: http://mailman.qth.net/archive/greenkeys/greenkeys.html
>>>>> Randy Guttery's 2001-to-2009 GreenKeys Search Tool: http://comcents.com/tty/greenkeyssearch.html
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> 
> --
> ---
> ----
> The above comments or recommendations are SWAG. Use at your own risk.
> 
> John, W9DDD
> 
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> 
>>>> Jordan Spencer Cunningham's GreenKeys Search Tool: https://teletype.net/gksearch
>>>> 2002-to-present greenkeys archive: http://mailman.qth.net/pipermail/greenkeys/
>>>> 1998-to-2001 greenkeys archive: http://mailman.qth.net/archive/greenkeys/greenkeys.html
>>>> Randy Guttery's 2001-to-2009 GreenKeys Search Tool: http://comcents.com/tty/greenkeyssearch.html
> 
> This list hosted by: http://www.qsl.net
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