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:
Jan. 12, 1982
Filed:
Feb. 26, 1980
Alain G Dumont, Saint-Vallier, FR;
Jeumont-Schneider, Puteaux, FR;
Abstract
A ringing device for a PABX comprising an alternating signal source and a direct current source connected to a supply line for supplying a ringing signal to subscriber lines. A centralized off-hook condition detection circuit is connected in series with the supply line and a switch, and in series with each subscriber's line is a local off-hook condition detection circuit and a bidirectional contact. At the time of any off-hook, the switch opens the alternating signal circuit, and the corresponding answering subscriber's line previously connected to the ringing signal supply line is connected to the switching network of the PABX before the switch recloses the circuit for supplying the ringing signal to the other called extensions.