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:
Mar. 15, 1988
Filed:
Jun. 07, 1985
Paul M Basehore, Sanford, FL (US);
Plessey Overseas Limited, Ilford, GB;
Abstract
To facilitate ring trip detection in a telecommunications exchange the ringing signal applied to a customer line is limited to provide a square wave output. Since when the customers instrument is 'on hook' virtually no direct current flows in the line, the square wave output has substantial 50--50 duty cycle and when the customer instrument goes 'off hook' the d.c. alters that duty cycle, by sampling the square wave signal and counting up for, say, positive samples and down for, say negative samples, any significant change in the duty cycle causes a counter to exceed a ring-trip threshold fairly rapidly. An algorithm and circuit using the algorithm to facilitate identification of 'ring trip' based on the above feature are disclosed herein.