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. 03, 1990
Filed:
Dec. 13, 1988
Applicant:
Inventors:
Kenneth A Houck, Haverhill, MA (US);
Dewayne A Spires, Plaistow, NH (US);
Assignee:
AT&T Bell Laboratories, Murray Hill, NJ (US);
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
H04M / ;
U.S. Cl.
CPC ...
379373 ; 379201 ;
Abstract
To accurately detect the short bursts of distinctive ringing signals within 100 milliseconds, a magnitude comparator produces a binary signal indicative of whether the instantaneous tip-ring voltage exceeds a predetermined magnitude. The binary signal is integrated over a predetermined period of time controlled by a timer. If the time integral is below a first predetermined value, the absence of ringing is detected; if above a second predetermined value, ringing is detected; if in between, the integrating interval is extended until the integral falls outside the two values.