The stimulus router system (SRS) is a novel type of neural prosthesis in which some of the current flowing subcutaneously between surface electrodes is routed to a target nerve by a passive implanted conductor . The implanted conductor connects a pick up terminal placed subcutaneously under a cathodal surface electrode to a delivery terminal placed on the target nerve. An external stimulator is connected to the surface electrodes to deliver current pulses. About 10~15% of the current flowing subcutaneously between the surface electrodes is diverted through the implanted conductor to the target nerve. This percentage was found to increase when the pick up terminal was provided with backing insulation and when the surface electrodes were small. The current required to stimulate a nerve was greatly influenced by current spread to the non-targeted tissues at the delivery terminal. Design of the delivery terminal that confines diverted current to the target nerve is important to ensure optimal performance of the system.