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. 25, 2003
Filed:
Jun. 26, 1998
Teruyuki Nishii, Tokyo, JP;
Canon Kabushiki Kaisha, Tokyo, JP;
Abstract
When detecting a signal from a communication network, signal detection is performed corresponding to the characteristics of a communication apparatus of a communication partner and the characteristics of the communication network, and to prevent erroneous detection of a signal due to a voice or the like. More specifically, using a tone detection function of a modem of a communication unit, a control unit determines if a signal of at least one period has been detected in accordance with detection parameters, i.e., a frequency, a level, and an on-time and an off-time, which correspond to a tone signal to be detected and which can deal with variations in the characteristics of the signal. When a signal of at least one period has been detected, changed detection parameters are calculated and set by adding margins to the frequency, the level, and the on-time and the off-time of the detected signal, and a signal of at least one period is again detected using the newly set detection parameters.