A microphone (1) picks up sounds. The sounds travel through a thin cable to a speech processor (2). You can wear the processor on a belt, in a pocket, or behind the ear. The processor converts the signal into an electrical code and sends the code back up the cable to the transmitter (3) fastened to your head. The transmitter sends the code through your skin to a receiver-stimulator (4 and 5) implanted in bone directly beneath the transmitter. The stimulator sends the code down a tiny bundle of wires threaded directly into your cochlea, the snail-shaped primary hearing organ. Nerve fibers are activated by electrode bands on this bundle of wires. Your auditory nerve carries the signal to your brain, which interprets the signal as a form of hearing.