A system and method of multi-symbol communications from a transmitter to a receiver via a channel, including transmitting signals as a waveform representing a sequence of symbols, each symbol of unit-interval duration and each symbol associated with its own signal level. This method includes graphically representing the waveform as an eye diagram having a horizontal time axis and a vertical signal level axis arranged to form one or more eyes, and using a sampling point in each eye to determine which signal the waveform in any unit interval represents. Each sampling point has a phase and a decision threshold. The method further includes identifying the eyes in the eye diagram, finding a convex polygonal region fitting within each eye, finding a largest rectangle fitting the convex polygonal region of each eye, and positioning the sampling point in each eye at a center of the rectangle of that eye.