Cellphones operate on a similar principle of connectivity.
With accessories, the unit can play Sirius or XM satellite radio, show which roads are jammed, connect to Bluetooth cellphones, operate an iPod and display images from a rearview camera.
(By comparison, the most common cellphones operate at a peak power of about 1.6 watts or less, and most studies have found no evidence linking the phones to health problems).
"We are seeing the emergence of a fourth screen," said Jerry Panagrossi, vice president for operations at Symbian, a developer of advanced cellphone operating systems, citing a historical progression of "movie, television, computer and now the smart-phone screen".
Apple and Microsoft share an enemy in Google, which has the most popular cellphone operating system in Android but does not have a strong presence in software for computers.
Nokia and Microsoft have been rivals for years in cellphone operating systems, with Nokia adopting Symbian software and shunning Windows Mobile.
Eric E. Schmidt's conference call last week about Google's new cellphone operating system, Android, was the opposite of a showy Steve Jobs keynote.
They orchestrated a string of acquisitions of companies with mobile-related technology, including Android, maker of a cellphone operating system; GrandCentral, a service for making calls that can bypass telephone lines; and AdMob, an advertising network for mobile applications.
Instead, with its share of the market for cellphone operating systems declining, Microsoft finds itself struggling to be the innovator rather than an also-ran mimicking Apple and Google.
In Google's letter to the commission, it said it did not screen applications for its Android cellphone operating system, but that it did reject apps that contained pornography or other objectionable material.
