The Mac’s stumble was in part because of pricing and in part because Mr. Jobs had intentionally restricted its expandability. Despite his assertion that a slow data connection would be sufficient, the gamble failed when Apple’s business stalled and Mr. Jobs was forced out of the company by the chief executive he had brought in, John Sculley.

In a similar fashion, Mr. Jobs is gambling that people will pay a premium ($499 or $599) for the iPhone and appears to have sought to limit its expandability.

The device is not currently compatible with the faster 3G wireless data networks that are driving sharp gains in cellular revenues in the United States, although several Apple insiders said the phone could be upgraded to 3G with software if Apple later decides to do so.

Moreover, Mr. Jobs also appears to be restricting the potential for third-party software developers to write applications for the new handset — from ringtones to word processors.

To be sure, this strategy has not limited the success of the iPod, which has become the defining hand-held consumer appliance and fashion statement in the last half-decade. The world of digital cellular phones, however, is rapidly becoming a simple extension of the world of personal computing. The leading handset makers — Microsoft, Motorola, Nokia, Palm, Research in Motion, Samsung and Sony Ericsson — are all pushing in the direction of making their devices increasingly look like PCs you can put in your pocket.

Mr. Jobs is moving in that direction, too, but it appears that he wants to control his device much more closely than his competitors.

“We define everything that is on the phone,” he said. “You don’t want your phone to be like a PC. The last thing you want is to have loaded three apps on your phone and then you go to make a call and it doesn’t work anymore. These are more like iPods than they are like computers.”