[GreenKeys] [Bulk] Re: [Bulk] Re: Telephoto machines?

[Jeffrey D Angus]

On 6/29/2015 3:34 PM, Jim Haynes wrote:
> Western Union developed an electrosensitive recording paper in the
> 1930s, which they named Teledeltos. As the ingredients were a secret
> one could worry whether it emitted toxic fumes.
That's it, and that doesn't surprise me.
> W.U. had a thing called a regulator-inverter in the telegraph office end
> of the circuit.  This applied AGC and also inverted the signal to that the
> highest voltage was for black and the lowest was for white.
And yes again, NOT having the inversion in the middle explains it.

-- 
Jeff-1.0
wa6fwi
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