For its next act, Apple is turning the iPhone into a personal assistant.
The company on Wednesday unveiled an eagerly awaited new version of the device, the iPhone 4S, that comes with a "virtual assistant," Siri, that recognizes voice commands by users to schedule appointments, dictate text messages and conduct Web searches.
Although the new phone is virtually indistinguishable on the outside from its predecessor, the iPhone 4, the company says it is packed with better technical innards, including a more advanced camera. The phone also includes a more powerful chip known as the A5, the same microprocessor that acts as the brains inside the iPad.
The company also said the new phone would run on two kinds of cellphone networks, GSM and CDMA, allowing its operation worldwide.
"When you think about it, only Apple could make such amazing software, hardware and services and bring them together into such a powerful, yet integrated experience," said Timothy D. Cook, Apple's chief executive officer, who introduced the new phone at an event here at the company's headquarters.
Despite the new features and the improved technology, Apple fans expressed disappointment on Twitter about the lack of a design change. Investors reacted as well, sending the stock down 5 percent.
Preorders for the iPhone 4S start on Friday; the phone goes on sale on Oct. 14. Prices start at $199 for a model with 16 gigabytes of storage.
Apple will continue to sell its older iPhone 4 through its wireless carrier partners, which will drop the price to $99 from $199 when customers commit to a two-year contract. An even older model of the device, the iPhone 3GS, will be free, instead of $99, with a two-year contract.
The new phone will be available on the AT&T, Verizon and Sprint networks.
Mr. Cook's appearance was his first at an event introducing a new Apple product since he took over as chief executive from Steven P. Jobs in August. Mr. Jobs was a master pitchman for Apple's new products, captivating audiences with introductions that seemed off the cuff but were always meticulously rehearsed.
Mr. Jobs, founder of the company, left the top job for health reasons, and became chairman of Apple's board.
Since the first iPhone was unveiled in 2007, Apple has come out with a new version each year, usually with an eye-catching new design, speedier technical performance and a fresh operating system packed with new features. While Apple generally has released the new versions in June, this one is coming out much closer to the crucial holiday selling season.
With every new iPhone, Apple faces the challenge of how to entice its legions of fans to upgrade to the new device and to convert the much larger pool of people who don't yet own one. The second task is the more difficult one, as mobile phones running the Android operating system by rival Google have flooded the market, with wider distribution from wireless carriers, more hardware choices and often cheaper price tags.
When the previous iPhone update was released, in June 2010, Apple and Google each accounted for about the same share of new smartphone sales. Since then the market has shifted dramatically in Google's favor. During the second quarter of this year, Android devices accounted for 43.4 percent of new smartphone sales to Apple's 18.2 percent, according to the research firm Gartner.
Both companies' mobile businesses are growing swiftly as they steal share from rivals like the maker of the BlackBerry, Research in Motion, that have fallen behind their technical innovations.
The iPhone is the most critical product in Apple's line-up and the largest source of its revenue, accounting for more than $13.3 billion -- almost half of total company sales -- in the most recent quarter.