An apparatus comprising: a communication facility configured to transcutaneously transmit a power signal to an implantable stimulator (104, 510), the implantable stimulator being configured to derive a compliance voltage from the power signal; a calibration facility configured to generate a calibration table indicating transmit power levels of the power signal required to achieve a plurality of distinct combinations of compliance voltages and maximum stimulation current levels by the implantable stimulator; and a compliance voltage facility configured to determine a maximum stimulation current level to be delivered by the implantable stimulator via one or more electrodes to one or more stimulation sites within a patient during a stimulation frame, determine an optimal compliance voltage that allows the implantable stimulator to deliver the determined maximum stimulation current level, and select, in accordance with the calibration table, a transmit power level that results in the implantable stimulator operating at substantially the optimal compliance voltage during the stimulation frame, wherein the compliance voltage facility is further configured to direct the communication facility to transcutaneously transmit a power signal having the selected transmit power level to the implantable stimulator during the stimulation frame. a communication facility configured to transcutaneously transmit a power signal to an implantable stimulator (104, 510), the implantable stimulator being configured to derive a compliance voltage from the power signal; a calibration facility configured to generate a calibration table indicating transmit power levels of the power signal required to achieve a plurality of distinct combinations of compliance voltages and maximum stimulation current levels by the implantable stimulator; and a compliance voltage facility configured to determine a maximum stimulation current level to be delivered by the implantable stimulator via one or more electrodes to one or more stimulation sites within a patient during a stimulation frame, determine an optimal compliance voltage that allows the implantable stimulator to deliver the determined maximum stimulation current level, and select, in accordance with the calibration table, a transmit power level that results in the implantable stimulator operating at substantially the optimal compliance voltage during the stimulation frame, wherein the compliance voltage facility is further configured to direct the communication facility to transcutaneously transmit a power signal having the selected transmit power level to the implantable stimulator during the stimulation frame. determine a maximum stimulation current level to be delivered by the implantable stimulator via one or more electrodes to one or more stimulation sites within a patient during a stimulation frame, determine an optimal compliance voltage that allows the implantable stimulator to deliver the determined maximum stimulation current level, and select, in accordance with the calibration table, a transmit power level that results in the implantable stimulator operating at substantially the optimal compliance voltage during the stimulation frame, wherein the compliance voltage facility is further configured to direct the communication facility to transcutaneously transmit a power signal having the selected transmit power level to the implantable stimulator during the stimulation frame.