(InfoWorld) - Imagine getting in a car and having it adjust its settings to the way you like them, grabbing a door handle that knows if you are authorized to open it, or shaking hands with someone and invisibly exchanging electronic business cards. Japan's Nippon Telegraph and Telephone (NTT)  is developing a system that can do these things and others by using your body to create a high-speed computer network.

The system, called RedTacton, grew out of a different research project and came about somewhat by accident. NTT researchers were working on an ultra-sensitive system for measuring voltages in chip circuits when an engineer discovered by chance that his body could carry a weak signal. Work began on that discovery as an additional project, and thus RedTacton was born.

RedTacton sends a signal through the very small electrical field that is emitted by, and exists around, the human body. The electric field replaces any cables or wireless link that might otherwise be used.

As the body is simply the carrier for the signal, a transmitter and receiver are needed. In a prototype that NTT built, the transmitter is a PC card plugged into a PDA (personal digital assistant). This card influences the body's electrical field when it is brought close to it, although it does not have to touch the skin. In a demonstration, the system worked when the PDA was placed in a jacket pocket.

On the receiving end is an optical sensor that uses a laser to interpret fluctuations in the electric field. The laser measures the effect the fluctuations have on a crystal that is part of the receiver, and in this way detects data being sent.

Using the body's electrical field for communications has been attempted before, but not successfully, according to Hideki Sakamoto, a senior manager at NTT's research and development strategy department in Tokyo. "As far as I know they all resulted in failure because they used electronic sensors."

Electronic sensors require two "probes," one of which has to stay in touch with the body. That's difficult to do without using something like adhesive tape, making such systems clumsy to use.

NTT's laser method makes for not only successful but also faster communications: data can be transmitted at up to 10Mbps, Sakamoto said.

Similar weak electrical fields can be found around many objects, including those made from metals, plastic, glass, ceramics and liquids, which means they can also be part of a RedTacton network. The system can work through clothing such as socks, shoes and gloves, and on both dry and oily skin. A person equipped with a sensor can exchange data with another person carrying a sensor by shaking hands, and between a person and a device by touching it, walking on it or sitting on it.

This allows devices to exchange information not just when two people touch, but also when they are in proximity to each other. For example, devices in the pockets of several people sitting around a meeting table would be able to talk to each other. This proximity-based transmission is limited by design to a range of about 10 centimeters to 20 cm, to avoid misuse and guard user security.

The system is safe, according to NTT, because no current flows into the body, and the electrodes in the transmitter and receiver are insulated. Only a few hundred milliwatts of power are required, and the system is within the Japanese government's guidelines for radio frequency exposure.

The company has created a prototype system that consists of transceivers in the form of PC cards and units that can be embedded in devices. It began offering these to some customers in April for a six-month field trial intended to test both the technology and business models around it.

The company envisages four major applications:

The first involves one-to-one services. In this application a RedTacton device in a user's hand or pocket communicates with devices embedded in the environment. For example, information on a product could be downloaded to a compatible cell phone when the user touches an advertising panel or a terminal could warn a person with bad eye-sight that they have picked up the wrong medicine bottle.

NTT is also considering using the system to make technology more intuitive: Imagine printing a document from a notebook PC in your hand by just touching a printer or exchanging electronic business cards with a handshake.

Because each person can carry their own transceiver, the system could identify users and personalize an environment to their taste. For example, the seats, mirrors and radio in a car could be adjusted as a person climbs into the vehicle.

The system is also being considered for computer networking. Tables equipped with sensors could form an ad-hoc computer network when people with suitably equipped PCs place their notebooks on them, or a computer could send audio files to an MP3 player without cables.

NTT's schedule for commercializing the technology will depend partly on the results of the trial.

"If the development goes well enough and we've come a long way, we hope to have commercial 'human area network' systems working sometime during 2006," said Toshiaki Asahi, a researcher at the company's strategic business creation team.

The company is also looking at refining the technology.

"We are thinking that we can use the system with the current types of transceivers, but we are also thinking of how to make them smaller. To do this, we have to shrink the [chips used in the system], but as we have developed all the key technologies this is not something that will take years," he said.

NTT's system isn't the only networking system available that uses touch to transmit data.

A subsidiary of Matsushita Electric Industrial Co. (Panasonic) commercialized a system last year that can transmit data through the body. Unlike RedTacton, it uses electric current and can achieve a transmission speed of just 3.7kbps, or about 3,000 times slower than RedTacton. It requires the user to wear a transceiver mounted on a wristband.

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