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:
Dec. 20, 1994
Filed:
Feb. 06, 1992
Applicant:
Inventor:
Shigefumi Odaohara, Yamato, JP;
Assignee:
International Business Machines Corporation, Armonk, NY (US);
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
H04M / ;
U.S. Cl.
CPC ...
379 97 ; 379386 ; 379 88 ; 379 98 ;
Abstract
A communication apparatus includes a Dual Tone Multi-Frequency (DTMF) noise signal detector for detecting a first DTMF noise signal caused by the apparatus and a second DTMF signal detector for detecting a DTMF signal transmitted from another apparatus. If self-induced DTMF noise is sensed, the second DTMF signal detector is disabled. As a result, the communication apparatus is able to distinguish the DTMF noise signal caused by said apparatus from the DTMF signal transmitted from another apparatus.