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:
Feb. 05, 1991
Filed:
May. 12, 1989
Katsuhiro Kakizawa, Kawasaki, JP;
Canon Kabushiki Kaisha, Tokyo, JP;
Abstract
A line switching apparatus includes receiving circuitry for receiving a line-connection request signal from an extension, discriminating circuitry for determining whether a connection is possible to the line when the connection request signal is received from the receiving circuitry, sending circuitry for sending a busy signal to the extension when the discriminating circuitry determines that connection to the line is impossible, detecting circuitry for monitoring the status of the line during sending of the busy signal by the sending circuitry, and detecting that the line is in a connectable state, and alarm circuitry for informing the extension of the fact that the line has been detected to be in the connectable state by the detecting circuitry.