[GreenKeys] Affordable current loop adapter

Sun May 18 11:22:49 EDT 2025

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
>>>
>>> ______________________________________________________________
>>> GreenKeys mailing list
>>> Home: http://mailman.qth.net/mailman/listinfo/greenkeys
>>> Help: http://mailman.qth.net/mmfaq.htm
>>> Post: mailto:GreenKeys at mailman.qth.net
>>>
>>>>>> 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
>>> Please help support this email list: http://www.qsl.net/donate.html
>>> Message delivered to deramp5113 at yahoo.com
>> ______________________________________________________________
>> GreenKeys mailing list
>> Home: http://mailman.qth.net/mailman/listinfo/greenkeys
>> Help: http://mailman.qth.net/mmfaq.htm
>> Post: mailto:GreenKeys at mailman.qth.net
>>
>>>>> 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
>> Please help support this email list: http://www.qsl.net/donate.html
>> Message delivered to david at stickelman.net
>
>
> ______________________________________________________________
> GreenKeys mailing list
> Home: http://mailman.qth.net/mailman/listinfo/greenkeys
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:GreenKeys at mailman.qth.net
>
>>>> 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
> Please help support this email list: http://www.qsl.net/donate.html
> Message delivered to w9ddd at tapr.org

-- 
---
----
The above comments or recommendations are SWAG. Use at your own risk.

John, W9DDD