Peter ha scritto:
> Does anyone have a link to a schematic of the first modems based apparently on
> LM555s ? Or anything similar ? Old RTTY modems, including valved ones, are not
> quite in this class although they come close.


Hmmm, applying a different voltage at pin 7, IIRC, you could make a 
rough FSK modem. Using Pin 4, OTOH, you could make AM or CW (Morse code) 
modulation.

I have basic 555 schematics.

Dario
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