Dropped Calls Miff iPhone 3G Users

"This is not surprising as the Infineon 3G chipset solution has never really been tested in the hands of users," Windsor writes. "This shows the risk of not going with a tried and tested solution."

Windsor says that because Infineon's "immature" chipset is embedded in the iPhone, Apple cannot remedy any 3G connection problems with a simple software update. Windsor does add that some iPhone owners will not experience the connection problems as it is only in areas where "the radio signal weakens...[and]the immaturity of the stack really shows."

Spokesmen for Apple and Infineon were not available for comment.

AT&T (T Quote) has already received complaints from U.S. iPhone users, although AT&T Wireless spokesman Mark Siegel says AT&T and Apple are working "to make sure everyone has a great experience.

"We couldn't be happier with the device," Siegel told TheStreet.com Tuesday. "This device is working great on our 3G network. We are thrilled with the customer interest in it."

Siegel did say that iPhone 3G users' experiences will depend on a variety of factors. "Are you in buildings? Are there tall trees? Are you in a mountainous area? Wireless networks are shared resources. The traffic has to be managed," Siegel said.

Nomura's Windsor says that the 3G connection problems are not being reported with other 3G devices on AT&T, which implies the problems are specific to the iPhone. While he isn't reducing his expectations for iPhone shipments yet, Windsor calls it "a worrying sign.