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. 23, 1977
Filed:
May. 03, 1976
Evan Philip Everson, Cedar Rapids, IA (US);
Walter Kidde & Company, Inc., Clifton, NJ (US);
Abstract
A system for monitoring a protected premises from a central station over telephone lines employs different audio tones sent back and forth over the lines. A random succession of audio tones from the central station interrogates the protected premises and is returned as a like succession of different tones to the central station where the latter tones are compared with the first to indicate a normal or a trouble condition at the protected premises or on the lines. When an alarm condition exists at the protected premises, still different tones are sent over the lines to cause an alarm alert at the central station. The entire system can be tested from the protected premises, including operation of the trouble and alarm circuits, without producing a trouble or an alarm alert at the central station.