Abstract: Apparatus and method for the prevention of echo signals in terminals connected to a network carrying telephony traffic. The echo prevention occurs prior to the introduction of signal delay by a network. The method and apparatus function to control echo contained in audio signals transmitted between the nodes of a network, wherein the audio signals experience delay in transit from node to node and wherein the echo controlling method is distributed across the nodes.

Abstract: A method for reducing the effects of transients on the DC off-set tracking stage and the symbol timing recovery stage in a full duplex or half duplex packet switched data communication system-in which transients occur in the receiver portion of the subscriber when the transmitter portion of a subscriber is keyed ON and OFF is described. The method is dynamically implemented such the DC tracking stage and the symbol timing recovery stage are set in a first "distortion ready" mode during the time that the transmitter is keyed on and off and is set back to a second "normal" mode after the transmission event is over. In the "distortion ready" mode, the symbol timing recovery stage is set in a "freeze" state such that it makes no further timing adjustments to a decision clock that it generates and the DC off-set recovery stage is set to a narrow bandwidth mode such that it does not track large variations in the DC off-set and amplitude in the received signal.