A system, including: an implantable neural stimulator including electrodes, at least one antenna and an electrode interface; a radio-frequency (RF) pulse generator module comprising an antenna module configured to send an input signal to the antenna in the implantable neural stimulator through electrical radiative coupling, the input signal containing electrical energy and polarity assignment information that designates polarity assignments of the electrodes in the implantable neural stimulator; and wherein the implantable neural stimulator is configured to: control the electrode interface such that the electrodes have the polarity assignments designated by the polarity assignment information, create one or more electrical pulses suitable for modulation of neural tissue using the electrical energy contained in the input signal, and supply the electrical pulses to the electrodes through the electrode interface such that the electrodes apply the electrical pulses to the neural tissue with the polarity assignments designated by the polarity assignment information.