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:
Dec. 30, 1986
Filed:
Oct. 25, 1984
Applicant:
Inventor:
Austin H Lesea, San Jose, CA (US);
Assignee:
Candela Electronics, Inc., Sunnyvale, CA (US);
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
H04M / ; H04M / ;
U.S. Cl.
CPC ...
379253 ; 379379 ; 379412 ;
Abstract
A personal branch exchange telephone system including improved interface circuitry to couple the system to outside telephone lines as well as to individual telephone sets on extension lines in the PBX system. The PBX system is connected to the telephone lines only through electromagnetic coupling and circuitry is provided to detect both ringing signals and loop current carried by the telephone lines.