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:
Mar. 24, 1987
Applicant:
Inventors:
Yves A Bonnet, Saint Laurent du Var, FR;
Christian Jacquart, Gattieres, FR;
Assignee:
International Business Machines Corp., Armonk, NY (US);
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
H04M / ;
U.S. Cl.
CPC ...
379382 ; 379377 ;
Abstract
The circuit of the present invention detects variations of a current I.sub.L flowing in a telephone line LL. A low-value resistor r is connected in series with line LL. A constant voltage generator is connected across this resistor. The current Is applied to resistor r by the contant voltage generator varies as a function of I.sub.L. This being so, a measurement of the variations of Is will reflect variations of I.sub.L and, therefore, can be used to detect both amplitude and directional variations of I.sub.L.