Lloyd Manaog Sarsoza

US Patent:

6721394, Apr 13, 2004

Filed:

Dec 9, 1999

Appl. No.:

09/458568

Inventors:

Tim Murphy - Ramona CA
Lloyd Sarsoza - San Diego CA
Martin Staszak - Poway CA

Assignee:

3Com Corporation - Santa Clara CA

International Classification:

H04M 124

US Classification:

379 2208, 379 24, 379 103, 379 101, 379 2701, 379413, 375222

Abstract:

A method for reducing audible noise in a telephone from a splitterless asymmetric digital subscriber line modem. The modem examines the shape of the power spectrum of fast retrain signals both when the telephone is on-hook and off-hook. By comparing the spectra, in particular the slopes of the spectra, the modem may determine the quality of the telephone that shares the telephone loop with the modem. The modem cuts back its transmitted power depending on the quality of the telephone by an amount that suppresses the audible noise in the telephone. In this manner, a customer may simultaneously use the telephone and the modem on the same telephone loop.