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.
Patent No.:
Date of Patent:
Jan. 27, 1987
Filed:
Jan. 29, 1985
Applicant:
Inventors:
Shoji Hirayama, Kanagawa, JP;
Mitsuharu Inada, Tokyo, JP;
Assignee:
Sony Corporation, Tokyo, JP;
Attorneys:
Primary Examiner:
Int. Cl.
CPC ...
H04Q / ;
U.S. Cl.
CPC ...
379 62 ; 455 88 ;
Abstract
A cordless telephone utilizes internally generated identifying codes to reduce crosstalk and the risk of wiretapping. When the handset unit is mounted on the base unit, a new identifying code is automatically generated and stored in the base unit, and then transmitted to the handset unit, which also stores it. When an incoming or outgoing telephone call is initiated, the two identifying codes stored in the base unit and the handset, respectively, are compared and, if they are not identical, the telephone call is cut off. Advantageously the identifying codes are randomly generated.