Sound is picked up through a tiny microphone housed in a headpiece that is worn at the ear. The sound is sent along a cable to a processor, a mini-computer that converts the sound into digital signals. The processor is worn on the belt or, in some models at ear level.
Once processed, the digital signals go back up to a transmitter (in some models, the transmitter and the microphone are in the same piece; in other models, the microphone is in a behind-the-ear piece that looks like a conventional hearing aid).
The transmitter, which is held by a magnet on the side of the head behind the ear, sends the coded signals via radio waves across the skin to the implant.
The implant delivers the signals to electrodes that have been inserted into the cochlea.
The electrodes stimulate the auditory nerve, sending impulses to the brain where they are interpreted as sound.