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:
Aug. 02, 1983
Filed:
Sep. 21, 1981
Theodore W Wagner, West Palm Beach, FL (US);
Siemens Corporation, Iselin, NJ (US);
Abstract
A ring trip detector for a subscriber line interface circuit which couples a two-wire subscriber line with the transmitting and receiving branches, respectively, of a four-wire line in a telecommunication exchange. The subscriber line interface circuit includes a two-to-four wire hybrid circuit having an off-hook detector; a ring generator for producing an AC ring voltage of given frequency for ringing a subscriber set connected to the subscriber line; and a ring relay for selectively connecting the hybrid circuit to the subscriber line when in a first position and connecting the ring generator to the subscriber line when in a second position. The ring trip detector includes a first circuit, which receives a first signal representing the off-hook condition of the subscriber set and a second signal that is synchronized with zero crossings of said ring voltage, for producing a synchronized off-hook signal at the next, subsequent zero crossing of the ring voltage after said first signal indicates the presence of the off-hook condition; and a second circuit, which receives the synchronized off-hook signal, for switching the relay to its first position.