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. 13, 1986
Filed:
Aug. 23, 1984
Applicant:
Inventor:
Sam G Cohen, Pleasantville, NY (US);
Assignee:
Timex Computer Corporation, Waterbury, CT (US);
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
H04M / ;
U.S. Cl.
CPC ...
179 / ; 179 / ;
Abstract
A telephone communications interface adapted to provide a data link for receiving and transmitting serial data via FSK modulated carrier signals over telephone lines to a computer. An operational amplifier in a duplexer circuit has a variable impedance feedback circuit, which is automatically adjusted by a computer subroutine to adjust the amplifier gain, so as to compensate for variations in the telephone company line impedance. The gain is adjusted to minimize the amplitude of any transmitted carrier signal, which might appear at the input of the conventional band pass filter for the receiver carrier signal.