Fiber Meets Frugality

Two cars shriek to a stop at a red light: a luxury Mercedes-Benz S600 and a Ford Taurus. As an onlooker, can you guess which car will boast a better sound and navigation system in the near future? You might be surprised at the answer, because luxury car technology will soon be available to more frugal consumers.

D2B SmartWire, developed and introduced in 2000 by Communication and Control Electronics Ltd. (C&CE) in Guildford, U.K., uses an unshielded twisted pair of copper wires to carry audio, video, navigation and communication data throughout the vehicle. The wire, which is similar to the Ethernet cable that connects a computer to a network, replaces more expensive fiber optic cables in upscale car audio systems.

The wire, which is both less expensive and easier to repair, was designed to offer the same functionality and quality found in the new Mercedes-Benz S-Class to midrange priced vehicles. Now a luxury audio and video system does not have to come at a luxury price, says C&CE.

SmartWire was developed as part of the Digital Data Bus (D2B), the networking protocol for automotive multimedia communication systems. C&CE worked with Philips Electronics NV, Matsushita Electric Industrial Co. and Becker GmbH in designing the protocol. The SmartWire chip, manufactured by C&CE, is what allows automakers and suppliers to design D2B systems that use copper wire rather than fiber optics. To date, all D2B systems are optical but by 2003-'04, SmartWire is expected to be standard equipment in some midrange vehicles, says Paul Nickson, chief technology officer for C&CE.

There are drawbacks to using fiber optic cable: It is difficult to package, requires specialized installers, is too expensive for high-volume cars and, significantly, has “minimum bending requirements,” meaning the transmitting capabilities can be ruined if bent too much. This is especially where D2B SmartWire becomes a more practical choice. In the crowded vehicle interior it can be bent over, under and around other components that would be obstacles to fiber optics.

The cost for SmartWire also is quite a bit less than fiber optic cables — the average cost per node of SmartWire is about $6 including connectors and wire. A typical fiber optic system in a Mercedes or Jaguar is about $75 for five nodes, “so the savings per car is around $50,” says Mr. Nickson. He notes that using copper wiring instead of fiber optics does not compromise speed, capacity, listening or viewing quality of the multimedia communication system. Mr. Nickson says the network has two bandwidth options: 5.6 megabits per second and 11.2 Mb/s. An example of capacity: An 11.2 Mb/s network can carry seven CD-quality audio channels.

A Japanese automaker will be first to incorporate SmartWire into vehicles in the next three years, with German and American manufacturers expected to follow.

Currently, the new Mercedes-Benz S-Class and C-Class models use D2B Optical, as does the new Jaguar X-Type. Fiber optics can accommodate greater data transmission than twisted copper wire, but it is not the technological solution of the future — it actually offers too much capacity for today's use but not enough for tomorrow, the company says. SmartWire was designed for the needs of consumers now and in the future.

Both the wire and optical networks are designed to connect radio, CD changer, amplifier, DVD, navigation system, computer, mobile phone and voice control devices into one system. From this, the driver is able to operate all components from just one dashboard, wheel-mounted or voice-activated controller.

Neither SmartWire nor fiber optic systems are designed to incorporate engine or safety controls. “Carmakers make a strict distinction between the safety and engine control bus (a databus, similar to D2B) and the multimedia and driver convenience bus. The engine/safety bus is not capable of streaming audio. Gateways are, however, used between networks to transport AC control commands, for example, or dashboard display information,” says Mr. Nickson.

A major plus for a D2B SmartWire network, Mr. Nickson says, is that it does not restrict the carmakers to certain brands or designs of equipment, especially because it has the scalability for tomorrow's technology. SmartWire is an “open” system that is fully compatible with existing protocols and those that will come along in the future. Therefore, car manufacturers can customize the network system with any combination of multimedia devices, as long as they are compatible with D2B.

No vehicle currently uses SmartWire, but integration is not far off. Many carmakers are evaluating its use because of its cost savings. At the beginning of June, the technology was presented to a leading forum of carmakers representing 75% of worldwide production, Mr. Nickson says.

Though SmartWire is a significant breakthrough for buyers of midpriced vehicles, its benefits likely will not be widely available to low-priced models. “Not all cars need the functionality. Low-end cars typically have a single box in the dashboard that does the radio/cassette function. In midrange cars, the functionality demanded by customers is higher and the options greater,” Mr. Nickson says.