Method and apparatus for detecting far end speech in a telephone apparatus. A speaker (14) produces far end sound from a far end signal, when received by the telephone apparatus. A microphone (12) generates a near end signal from near end sound, for transmission from the telephone apparatus. A hybrid (24) which passes the near and far end signals from an external two wire link (30) to and from the speaker and microphone, on respective first and second paths (1, 2) of a four wire link (28). Muting of the near end signal is effected when signal derived from the first path (1) of the four wire link (28) is detected as being representative of a condition of existence of far end signal. Signal determined as representing sidetone signal deriving from the near end signal from the speaker (14), and appearing in the signal on the first path (1) of the four wire link (28), pursuant to traverse of part of the near end signal through the hybrid, is subtracted from the signal derived from the first path (1) of the four wire link (28). Existence of the condition of existence of far end signal is then determined on the basis of the result of the subtraction.

 
Web www.patentalert.com

< Variable sidetone system for reducing amplitude induced distortion

< Method and system for management and notification of electronic certificate changes

> Discovering stolen or lost network-attachable computer systems

> Method and apparatus for gradual application of a hitless monitoring access to a communications circuit employing a guided transmission media

~ 00234