System and method for controlling distortion in the POTS band in a dual POTS and discrete multi-tone communication system

A digital signal processor for minimizing signal distortion at the customer premises in a discrete multi-tone communication system comprising:

• means for generating a probe signal;
• means for directing the transmission of the probe signal in the upstream data channels;
• means for measuring that portion of the downstream signal power introduced by the probe signal;
• means for determining an upstream data channel signal power cutback level;
• means for determining a downstream channel signal attenuation;
• and
• means for commanding the central office to adjust the downstream data signal transmission power.

An ADSL transmission unit—remote configured to minimize signal distortion at the customer premises comprising:

• a hybrid;
• an analog front end in communication with an ADSL transmission unit central office configured to transmit upstream data and to receive downstream data in accordance with the ADSL-DMT standard;
• and
• a digital signal processor configured to generate a probe signal for transmission across the upstream data channels, the digital signal processor further configured to measure the resulting noise at the analog front end in the downstream data frequency range, the digital signal processor further configured to optimize the upstream power cutback in response to the resulting noise, the digital signal processor further configured to command an ADSL transmission unit—central office to adjust the downstream transmission power in response to the optimized upstream power cutback and a predetermined acceptable noise threshold.