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:
May. 20, 1980
Filed:
Aug. 14, 1978
Jacob Cepelinski, Ottawa, CA;
Mitel Corporation, , CA;
Abstract
A circuit for efficiently applying tones or other signals to a line circuit which has a variety of conditions such as being split from the central office, and having a telephone set connected thereto either on hook or off hook. The invention is comprised of a tip lead and a ring lead having one end for connection to a central office and another end for connection to a subscriber's telephone set. A low impedance signal source including line current conducting means is connected in series with the tip or ring lead. A switchable resistance is provided for connecting a circuit path between the tip and ring leads at the telephone set end of the tip and ring lead. Preferably the low impedance signal source including the line current conducting means has a resistance which is 25% or less than the off hook impedance of the telephone set.