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:
Oct. 02, 2012
Filed:
Sep. 24, 2008
Kimiaki Ogawa, Tokyo, JP;
Kimiaki Ogawa, Tokyo, JP;
Oki Data Corporation, Tokyo, JP;
Abstract
A communication terminal apparatus is provided capable of preventing a misunderstanding that the external attachment telephone is hooked up, so that the external attachment telephone can be correctly shifted to a receiving mode. In the apparatus, a ring signal detecting section detects a ring signal sent by a line exchange machine from a line; and a hookup detecting section monitors a line voltage of the line and detects a hookup of an external attachment telephone. In the hookup detecting section, a line voltage detecting section detects the line voltage on the line; a reference voltage outputting section outputs a reference voltage; a threshold value voltage switching section switches to a threshold value voltage representing a first voltage level or switches to a threshold value voltage representing a second voltage level; and a voltage comparing section compares the reference voltage with the line voltage when the ring signal is detected. When a comparison result indicates that a difference is or over a threshold value voltage representing the first voltage level, it is detected that the external attachment telephone is hooked up.