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. 26, 1994
Filed:
Jun. 07, 1991
Donald S McGinn, Almonte, CA;
Northern Telecom Limited, Montreal, CA;
Abstract
A line interface circuit for coupling signals between a telephone line and a hybrid circuit includes a loop driver circuit for supplying energizing current to the telephone line and for driving the telephone line with alternating current signals. A loop current detector connected in series between the telephone line and the loop driver circuit, generates a voltage signal in response to current flow in the telephone line. Amplifier circuits are arranged to be responsive to differential signals on the telephone line, and to signals from the hybrid circuit, for generating a composite signal. The composite signal and the voltage signal are combined in a network having an output connected to control the operation of the loop driver circuit so that the telephone line is terminated with a preferred impedance.