Telegraphy – Systems – Printing
Patent
1962-06-12
1982-06-01
Birmiel, Howard A.
Telegraphy
Systems
Printing
178 2213, H04L 902
Patent
active
043329772
ABSTRACT:
1. A teletypewriter privacy system comprising a first and a second pair of terminals responsive to printing-telegraphy signals having start bauds; means for generating program signals having a fixed timing relationship with the start bauds of said telegraphy signals; a mixer circuit coupled between said terminals, and responsive to said program signals; said mixer circuit including a first switch coupled to said first pair of terminals, and a second switch coupled to said second pair of terminals, means responsive to a start baud at said first pair of terminals for maintaining said first switch operative to couple said first pair of terminals to said mixer circuit for one telegraph character, means responsive to a start baud at said second pair of terminals for maintaining said second switch operative to couple said second pair of terminals to said mixer circuit for one telegraphy character, first polarized switch means responsive to the telegraphy signal at the first pair of terminals and the program signal for selectively activating said second switch, and second polarized switch means responsive to the telegraphy bauds at the second pair of terminals and the program signal for selectively activating said first switch. 19. In combination, an electrical switching circuit for generating four pseudo-random binary electrical signals that correspond to W, X, Y and Z, and another electrical circuit for combining, through logical OR gates, said electrical signals to generate a further electrical signal representing WXYZ+XY+Z W, for use as a key for encoding a communication signal.
REFERENCES:
University of Michigan Technical Report No. 90, "Introduction to Linear Shift-Register Generator Sequences", Oct. 1958, Birdsall and Ristenbatt.
MIT Lincoln Lab, Technical Report No. 95, dated Sep. 12, 1955, "Several Binary Sequence Generators", Zierler.
MIT Lincoln Lab Group Report 34-24, Jul. 1954, "Two Pseudo-Random Sequence Generators", Zierler.
MIT Lincoln Lab, Group Report No. 34-63, "Linear Recursive Sequences I", Dec. 1957, and Linear Recurring Sequences, Aug. 1958, Zierler.
American Standard Inc.
Birmiel Howard A.
Crooks Robert G.
Salerno, Jr. James J.
Sinnott John P.
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