Abstract: In a method, system and apparatus for providing an endpoint-to-endpoint transcoding free connection, a customer premises equipment (CPE) at a first or second endpoint encodes and decodes voice data received from and sent to a respective one of first and second media gateways according to an initial codec type. The first and second media gateways perform a Transcoding Free Operation (TFO) negotiation to determine if there is a common codec type among the first and second media gateways and first and second endpoints. If such a common codec type is determined, the first and second media gateways switch from encoding voice data according to the initial codec type to the common codec type and send an indication of the switch to the respective one of the first and second endpoints.

Abstract: A modem-based echo cancellation enhancement for digital communications networks is provided. The effects on echo cancellation of non-linearity in a far end echo path in a digital telephone system are reduced by introduction of non-linearities into the near end signal prior to generation of the echo cancellation signal. Near end signal is sampled after linear to PCM conversion. A PCM to linear conversion is added prior to the echo canceler. The near end delay line can be provided between the converters to delay the signal as PCM samples, thereby reducing delay line memory requirements.