[GreenKeys] ASCII/RS-232/AFSK Interface for the Model 15 Teletype

[W2HX]

Ok Mike. Just a question about the theory of operation of this circuit. From what I can surmise, RC2 on the U2 seems to be doing the signaling for the selector magnets. Meaning, I would expect the baudot code to be present on RC2 (am I correct?) can you elaborate on the functions and interplay of RC1 and RA5? All three seem to be involved in this output circuit.

I think others would also be interested in the theory here. thanks

73 Eugene W2HX
Subscribe to my Youtube Channel: https://www.youtube.com/c/w2hx-channel/videos



-----Original Message-----
From: greenkeys-bounces at mailman.qth.net <greenkeys-bounces at mailman.qth.net> On Behalf Of Mike Douglas via GreenKeys
Sent: Sunday, June 26, 2022 5:44 PM
To: Greenkeys <greenkeys at mailman.qth.net>
Subject: Re: [GreenKeys] ASCII/RS-232/AFSK Interface for the Model 15 Teletype

Eugene,

Unfortunately, no, this board can’t easily be configured to work with an external loop supply.

Mike

> On Jun 26, 2022, at 12:06 PM, W2HX <w2hx at w2hx.com> wrote:
> 
> What a great project! I have a question. Could the circuit be modified to only key an existing loop without the need for this board to generate the loop current itself? I would imagine maybe less components needing installation and some jumpers but I was wondering your opinion of that.
> 
> 
> 73 Eugene W2HX
> Subscribe to my Youtube Channel: 
> https://www.youtube.com/c/w2hx-channel/videos
> 
> -----Original Message-----
> From: greenkeys-bounces at mailman.qth.net 
> <greenkeys-bounces at mailman.qth.net> On Behalf Of Mike Douglas via 
> GreenKeys
> Sent: Sunday, June 26, 2022 12:35 PM
> To: GREENKEYS BULLETIN BOARD <greenkeys at mailman.qth.net>
> Subject: [GreenKeys] ASCII/RS-232/AFSK Interface for the Model 15 
> Teletype
> 
> I recently made a new version of the subject interface board that incorporates the changes I made to the prototype unit that you may have seen in a few videos I posted. I've made a web page to document this new version - see the link below. I still need to write a user manual and finish a small wish-list I've given myself for the firmware.
> 
> https://deramp.com/model15_interface.html
> 
> I have a number of bare PCBs of this new version if anyone wants one - just contact me. I'd still like to work with someone to tweak components and firmware as needed for a holding magnet configuration.
> 
> Mike
> 
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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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>>> 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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