Patent ID: 6765967
Filing Date: 2004-07-20
Classification: H04B,H04L

Abstract:
For use in a network line card, an enhanced codec apparatus, comprising:a digital signal processor circuit; a digital interface port with a first coupling to said digital signal processor circuit and a second coupling to a digital network interface port of a digital telecommunication network; a digital conversion subsystem comprising a DAC wherein said DAC has a digital input coupled to receive a digitally encoded signal sample derived from said digital interface port and an analog output coupled to a first analog signal port, said digital conversion subsystem also comprising an ADC that has a digital output and an analog input; an echo canceller processing module comprising an adaptive filter and a summing module, said echo canceller processing module controllably coupled to said digital signal processing circuit and operatively coupled to receive at an X-input to said adaptive filter a digital representation of a signal derived from said digital interface port, said echo canceller processing module also operatively coupled to receive at a first input to said summing module, a signal that passes through a second analog signal port, said echo canceller processing module also operatively coupled to receive at a second input to said summing module, an output signal from said adaptive filter, said echo canceller processing module operative to cancel an echo component which leaks from the output of said first analog signal port back into the input of said second analog signal port when said first and second analog signal ports are coupled to a subscriber line; a pulse decoder processing module controllably coupled to said digital signal processing circuit and having an input operatively coupled to the output of said summing module, said pulse decoder processing module operative to regenerate a PCM data stream; and a protocol detect processing module controllably coupled to said digital signal processing circuit, said protcol detect processing module operative to detect a transmission protocol used within said POTS portion of said subscriber line and select a pulse decoder mapping operation in response thereto; wherein said enhanced codec apparatus is adapted to receive at the analog input to the ADC a signal comprising a high speed pulse upstream modem data signal, thereby enabling a substantially symmetric pair of high-speed pulse modem communication channels in the upstream and downstream directions.