Flexible asymmetrical digital subscriber line (ADSL) receiver, central office using same, and method therefor

An ADSL receiver (200) receives an upstream modified ADSL signal and an ISDN signal from a remote terminal (32) on a twisted-pair copper wire (18). An ADSL transmitter (100) of the remote terminal (32) transmits the ADSL signal in a frequency range above an ISDN frequency range so that the ADSL signal does not overlap the frequency range of the ISDN signal. In one embodiment, the ADSL receiver (200) includes a band pass filter (201), an analog-to-digital converter (203), a decimator (205), a fast Fourier transform (210), and a digital signal processor (212). The decimator (205) converts the ADSL signal back to base band, thus allowing an ADSL signal source to simultaneously utilize the telephone line with an ISDN signal source, without significantly reducing ADSL throughput.