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:
Oct. 04, 1988
Filed:
May. 22, 1986
Applicant:
Inventors:
Zbigniew B Styrna, Kanata, CA;
Douglas C Oddy, Ottawa, CA;
Assignee:
Mitel Corp., Ontario, CA;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
H04M / ;
U.S. Cl.
CPC ...
379234 ; 379413 ; 379398 ; 379324 ;
Abstract
A trunk circuit is disclosed for coupling a bidirectional lead pair, such as balanced tip and ring leads, to a pair of unidirectional leads such as unbalanced input and output leads. The trunk circuit incorporates a small inexpensive transformer for effecting this coupling and for providing large common mode signal isolation and correct longitudinal balance. Circuitry is provided for matching the nominal balanced AC and DC line impedances. The trunk circuit also provides circuitry for generating dial pulse signals under control of a microprocessor or other external controller.