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:
Nov. 14, 1989
Filed:
Jun. 08, 1988
Applicant:
Inventors:
Kenichi Takeuchi, Tokyo, JP;
Shin Saito, Tokyo, JP;
Shoji Araki, Kanagawa, JP;
Atsushi Nakayama, Kanagawa, JP;
Assignees:
Nippon Telegraph and Telephone Corporation, Tokyo, JP;
Sony Corporation, Tokyo, JP;
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
H04M / ; H04N / ;
U.S. Cl.
CPC ...
379 54 ; 379 96 ; 358 85 ;
Abstract
A television telephone system utilizes a tone signal of a predetermined duration. The tone signal has a plurality of frequencies and is positioned at the starting portion of a transmission signal. The tone signal reduces the possibility of mis-detection of signals during reception and allows video signals to be transmitted more satisfactorily.