A digital based two wire proximity transmitter system and a method for calibrating the system, wherein the transmitter includes a customized linearization table uniquely generated during calibration to take into account the unique impedance properties of a particular probe/coaxial cable configuration. During calibration, the probe is positioned adjacent a calibration target. The calibration target is selected to have the same material characteristics as the target to be monitored during actual operation of the transmitter in the field. At a fixed distance between the probe and calibration target, the resonant frequency of the probe/cable system is determined. Thereafter, utilizing this resonant frequency to excite the probe, the voltage response of the probe/cable system is determined as the distance between the probe and the target material is incrementally changed. The voltage output is used to build a table for incremental distances, wherein each distance is characterized by a non-linear output that has been equated to a linear output. This uniquely generated table is subsequently downloaded into the transmitter for reference during monitoring.