The NeuroTalkTM interface, described in a companion paper allows for a standardized method of communication with implanted modules that contain custom application specific integrated circuits (ASIC). Here, we describe an example of one such ASIC that has been designed for use in a visual prosthesis. The ASIC is small enough to be incorporated within a 16-channel multielectrode stimulation array implanted in the cortex. In this paper we describe a version designed to operate over a 4-wire buss called NeuroTalk 2. Other versions of the ASIC operate using a single coil input for power and data, over a transcutaneous magnetic link.