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

[Harold Hallikainen]

Nice! Why the different values of R2 for holding and pulling magnets?
Maybe the lower resistance of holding magnet coils in parallel?

What is the purpose of R11 across the selector magnet?

It looks like the AFSK input is going to an analog comparator input. Is
this using period timing to demodulate the AFSK?

Nice work!

Harold
https://w6iwi.org


On Sun, June 26, 2022 9:34 am, Mike Douglas via GreenKeys wrote:
> 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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