The growing demand for input devices designed for the severely handicapped led to development of modular features for the open architecture multiple master multiple slave (M3S) system. With its central safety monitor, M3S allows individuals suffering from cerebral palsy, paraplegia, or multiple sclerosis, and other physically debilitating illnesses greater autonomy by allowing them to access a wide range of input devices tailored to a specific user, e.g., joysticks, keypads, head-control modules and speech recognizers. These input devices, which are equipped with basic configuration abilities, are operated with DSP cores and additional circuitries to maintain optimal control and high levels of safety, and may be modified or expanded with minimal adjustments.