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. 03, 2000
Filed:
Dec. 22, 1997
Costas Papadopoulos, Acton, MA (US);
David J Truesdell, Acton, MA (US);
VXI Corporation, Rollinsford, NH (US);
Abstract
A telephone headset interface circuit is coupled to a telephone line to extract power for use by a headset amplifier and is particularly adapted for use with telephone handsets having dynamic or electret microphones. The telephone line connects a telephone to a service system, such as a Central Office, a PBX system, or a Key system. The interface circuit includes a power extraction circuit having a plurality of circuit portions, each one coupled to a corresponding one of the telephone line wires for providing a predetermined output voltage, so that substantially identical electrical impedance characteristics are introduced to each such wire. An amplifier is coupled to the telephone handset such that the predetermined constant output voltage is coupled to the amplifier to power the amplifier from the telephone line when the telephone includes an electronic microphone handset. An isolated rectifier circuit powers the amplifier when the telephone includes another handset other than an electronic microphone handset, such as a carbon microphone handset or a DC powered handset.