[GreenKeys] [External] Two-tape TTY for crypto

[Jim Haynes]

There's a funny story connected with this in the book "Old Wires and
New Waves" by Alvin F. Harlow, 1936.  When WW-I was over the Signal
Corps put on a show for the press, showing interesting stuff developed
during the war.  One of these was a machine that would translate
between English and French.  They could put a tape containing a passage
in English into the tape reader and the French equivalent would come
out on the printer.  And vice-versa.

Of course it was really a hoax.  What they had done was create English and 
French texts containing exactly the same number of characters. And a hand 
made key tape that would convert one into the other by XOR character by 
character.

Harlow's book is an interesting read in general.  It tells the state
of the wire and radio voice and telegraph art as of 1936.

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 	"Ya can argue all ya wanna, but it's dif'rent than it was."
 	"No it ain't! No it ain't!  But ya gotta know the territory."
 		Meredith Willson, The Music Man