The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.

The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.

Date of Patent:
Sep. 15, 1992

Filed:

Dec. 17, 1990
Applicant:
Inventors:

John M Saltwick, Phoenix, AZ (US);

Dean Scarinci, Glendale, AZ (US);

Assignee:

Syntellect Inc., Phoenix, AZ (US);

Attorney:
Primary Examiner:
Int. Cl.
CPC ...
H04K / ;
U.S. Cl.
CPC ...
380-6 ; 380-7 ; 455-1 ;
Abstract

A system and method are disclosed for preventing intelligible interception of information signals transmitted over a two-direction line. A masking signal is applied through a hybrid circuit at the receiving end of the line, and this masking signal, which appears on the line together with the information signal, prevents the intelligible decoding. Only at the receiving end of the line, where the hybrid circuit attenuates the masking signal which it receives at its receive port, can intelligible decoding take place. Signal processing techniques used at the receiving end permit larger amplitude masking signals to be used, thus creating even greater confusion for an unauthorized detecting mechanism which is coupled to the line.


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