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:
Jul. 02, 1991
Filed:
Feb. 02, 1990
Donald F Parsons, West Chester, PA (US);
Brian D Greenwald, Chester Springs, PA (US);
John J McGrath, Kennett Square, PA (US);
Michael Dudek, Philadelphia, PA (US);
Leo D Parsons, Chester Springs, PA (US);
Communications Test Design, Inc., West Chester, PA (US);
Abstract
An alarm system suitable for use in a telecommunications network in which a central switching system is capable of selectively providing a signal of a predetermined polarity to a plurality of remotely located stations without being dependent upon or impeding the ability of the central switching system to process relatively high volume communications traffic. Each of the remote stations is connected to the telecommunications network by an electrical conduction path. The stations are substantially unresponsive to the predetermined polarity signal. In response to an alarm indication signal, the system effects a reversal in the polarity of the signal provided to a selected subset of the remote stations. Each station in the selected subset responds to the polarity reversal by indicating an alarm condition.