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:
Sep. 04, 1979
Filed:
Apr. 24, 1978
William F MacPherson, Winfield Township, DuPage County, IL (US);
Irving M McNair, Jr, Mendham Township, Morris County, NJ (US);
Bell Telephone Laboratories, Incorporated, Murray Hill, NJ (US);
Abstract
A miniature electronic bridge lifter for bridged telephone lines which can be mounted directly on the protector unit in the central office includes an impedance inserted serially in each side of the loop for isolating the nonactive loops from the central office termination and for switching to a low impedance connection whenever a party on one of the bridged line connections goes off-hook. A combination semiconductive and resistive voltage divider detects the voltage across the loop. The resistive component is essentially the only cross-coupling between the telephone lines. When the line voltage falls below a preselected threshold, indicating that the connected party has gone off-hook, a switch is operated to bypass the series impedances and establish a low-loss path to the common line.