Patent ID: 7734036

Claim:
Apparatus for controlling attenuation to optimize voice quality in a communications network, the apparatus comprising: an echo canceller at a first network node through which a call supported by the first network node and a second network node is established; the echo canceller coupled between a first network interface and a second network interface, and having: a receive path for coupling a far-end signal from the first network interface to the second network interface; a transmit path for coupling a near-end signal from the second network interface to the first network interface; an echo canceller circuit coupled to the receive path and the transmit path for filtering far-end echo from the near-end signal; a first attenuator in the receive path and a second attenuator in the transmit path, the first and second attenuators coupled immediately following the echo canceller circuit and before the second network interface; and a processor in communication with the echo canceller that is configured to: set a minimum dynamic attenuation echo return loss (ERL) threshold above a minimum expected ERL associated with optimal operation of the echo canceller circuit; set the first and second attenuators to an initial attenuation value upon establishment of the call; and measure ERL based on a first power level at a first point between the echo canceller circuit and the first attenuator and a second power level at a second point between the echo canceller circuit and the second attenuator and if the measured ERL is greater than the minimum dynamic attenuation ERL threshold, reduce the attenuation value of at least one of the first and second attenuators at an incremental rate until either (a) ERL, measured after each attenuation reduction, reaches the minimum dynamic attenuation ERL threshold or (b) both attenuation values reach a minimum attenuation value.