A method of modulating signal transduction andor cleavage in Tumor Necrosis Factor Receptors is provided. The system includes a storage unit for a dispersion liquid containing the charged phoretic particles dispersed therein, a stiffer for stirring the dispersion liquid, a substrate-holder for holding the substrate in the dispersion liquid, and a voltage source for applying a voltage to the electrodes formed on the substrate thereby depositing the electrophoretic particles on the electrodes. The subscriber loop and subscriber instrument reflect the digital voltage audio signals to the transmit section.