Japanese company Nippon Telegraph and Telephone Corporation (NTT) claims to have developed the first viable Human Area Network (HAN) device, enabling fast data transfer between devices using the human body as a conduit.
NTT reckons this latest advance on the wireless Personal Area Network concept - dubbed RedTacton - can transmit data over the surface of the skin at up to 2Mbps. Where it differs, though, from previous offerings, is that a RedTacton-enabled device does not have to be in direct contact with the skin - only within about 20cm. NTT explains the technical background:
Instead of relying on electromagnetic waves or light waves to carry data, RedTacton uses weak electric fields on the surface of the body as a transmission medium. A RedTacton transmitter couples with extremely weak electric fields on the surface of the body. The weak electric fields pass through the body to a RedTacton receiver, where the weak electric fields affects the optical properties of an electro-optic crystal. The extent to which the optical properties are changed is detected by laser light which is then converted to an electrical signal by a detector circuit.
RedTacton can also "transmit" through clothing or shoes, allowing the useful possibility of downloading MP3s through a floor-based sensor while dancing the Lambada. What's more, you can swap files by straight human contact, so two filesharers equipped with RadTacton devices can indulge in torrid illegal P2P activity and have sex at the same time.
http://www.theregister.co.uk/2005/03/23/human_area_network/