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:
Jan. 10, 1995
Filed:
Jun. 23, 1993
Applicant:
Inventors:
Heimo Lahdemaki, Pirkkala, FI;
Jaakko Sippola, Tampere, FI;
Assignee:
Nokia Telecommunications Oy, Espoo, FI;
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
H04M / ;
U.S. Cl.
CPC ...
379410 ; 379406 ; 379407 ; 379411 ; 379402 ; 370 32 ; 370 321 ; 370 24 ;
Abstract
Converging of an echo canceller (4A-D) integrated into a telephone exchange (1, 2) is initiated at the start of a telephone call by an internal command of the telephone exchange given by a call control (2) of the telephone exchange as soon as the call control (2) has observed an off-hook state of a called subscriber connection. The command causes the echo canceller (4A-D) to transmit a test signal to the echo path for converging the echo canceller before appearance of the speech signal.