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:
Jul. 28, 1992
Filed:
Feb. 25, 1991
Applicant:
Inventors:
Kuniyoshi Marui, Saitama, JP;
Kiyoshi Hattori, Tokyo, JP;
Assignee:
Kabushiki Kaisha Toshiba, Kanagawa, JP;
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
A04Q / ;
U.S. Cl.
CPC ...
455 332 ; 455 541 ; 455 677 ; 379 63 ;
Abstract
Radio telephone apparatus for use in a cellular mobile telephone system includes an alarm to inform a user of a drop in signal strength of radio frequency signals received over an established communication link. Such a drop occurs, for example, when the user is approaching the boundary of a service area. Further, the mobile unit detect the presence or strength of a tone signal modulated on at least one of the received radio signals. The mobile unit disconnects the telephone link and returns to the standby mode if the tone signal is lost or becomes too weak.