[GreenKeys] Keyer KY-463A?

[Jim Haynes]

On Sun, 16 Feb 2020, Nick England wrote:
> So adding all this together, makes me guess that the KY-463A/FGC was used to
> convert keyed tones to TTY loop signals. The keyed tones presumably came
> from someone listening to the other guy's RTTY transmissions.
> 
My guess is that this means converting on-off keyed tones to loop signals.
Where the on-off keyed tones are used at a station to make it convenient
to send TTY signals at audio levels to nearby equipment.