It was at the last Convergence two years ago that automakers from around the world set aside their fiercely competitive ways and agreed to jointly create a common architecture that would usher advanced electronics into future vehicles.

This year, the Automotive Multimedia Interface Collaboration (AMI-C) rolls out five "proof of concept" vehicles to demonstrate the possibilities for an open architecture enabling entertainment, communication and information devices to operate in vehicles.

But at least one AMI-C member expresses frustration at the slow movement of the consortium.

Karl-Thomas Neumann, director of electronics research at Volkswagen AG, says forming AMI-C was the right thing to do, and that there's nothing wrong with the vision. "The problem my company has is that progress is too slow," Mr. Neumann says in a panel discussion. "Maybe having 12 different companies is too big a challenge."

The member companies are DaimlerChrysler AG, Ford Motor Co., General Motors Corp., Renault SA, Toyota Motor Corp., Nissan Motor Co. Ltd., PSA Peugeot Citroen, Fiat Auto, Honda Motor Co. Ltd., Mitsubishi Motors Corp., Volkswagen AG and BMW AG.

But the 12 companies have not yet agreed on a protocol for a common architecture. Mr. Neumann says the organization "needs a fundamental change."

With 12 separate corporate cultures and seven different languages, AMI-C is "the auto industry's version of the United Nations," says Michael Noblett, AMI-C program manager. He says the group has made tremendous progress.

As evidence, he points to five cars in the AMI-C booth at Convergence, all of them suited with a standard architecture allowing cell phones, personal digital assistants and other devices to be interchangable from vehicle to vehicle.

The five vehicles are an Infiniti I30, Lincoln Navigator, Acura 3.2 TL, Oldsmobile Aurora and Lexus GS300.

"It's really here," Mr. Noblett says of the age of mobile connectivity. "It's not smoke and mirrors."

The next big challenge for the 12 partner companies is to define the specifications for the AMI-C architecture, likely within the next two years.

Once "Release 2" is decided, the floodgates will open as suppliers can begin producing countless gadgets to interact seamlessly in vehicles, many of them wirelessly, thanks to Bluetooth technology.

For instance, the same phone a person uses at home could operate in the car. "I don't want a different phone in the office, in the home. When I leave the house in the morning, I want to walk out with the same phone and keep talking while I'm in the car. The technology exists. The question is how to connect it.