A method and apparatus is disclosed for reducing the error rate in a received signal by determining and establishing an optimal slice point for a decision device, or optimal operational parameters. In one embodiment, a processor monitors a received signal to determine signal characteristics, such as a peak signal level or phase value. A table look-up operation may occur in a data table or other processing may occur and, based on the signal characteristics, an optimal slice point may be determined. In one embodiment the look-up operation may also reveal one or more optimal operational parameters that, if adopted, will further reduce the error rate. A receiving station may communicate these optimal operational parameters to a transmitting station to modify operation of the transmitting station. Also disclosed is a method and apparatus for self-testing a communication system and channel to determine optimal slice points and operational parameters.