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. 26, 1985
Filed:
Jan. 27, 1982
Teruo Matsufuji, Koganei, JP;
Iwasaki Tsushinki Kabushiki Kaisha, Tokyo, JP;
Abstract
A subscriber circuit in a time-division telephone switching system having a supervisory circuit connected to a subscriber telephone set for supervision of incoming calls, call-answering, line-busy and on-hook supervision on the telephone set. A common control circuit receives signals from the supervisory circuit through a scan circuit and when it receives a signal indicating that the handset has not been properly replaced. A howler tone source of a howler tone transmission circuit generates a low-level howler tone signal which is modulated by a modulator in the howler tone transmission circuit. This modulated tone signal is applied to a demodulator in the subscriber circuit through a speech connecting network for the transmission of speech to and from the telephone set without further need of connecting link such as a trunk line or the like. The telephone set converts the demodulated tone signal to a continuous howler tone audible signal.