Apple

Some people have raised red flags regarding AT&T's limits on the use of FaceTime on the upcoming iOS, alleging the restrictions could go against Federal Communications Commission rules.

"Over-the-top communications services like FaceTime are a threat to carriers' revenue, but they should respond by competing with these services and not by engaging in discriminatory behavior," senior staff attorney at Public Knowledge John Bergmayer said in a statement. Public Knowledge is a nonprofit organization that works on Internet law.

The "discriminatory behavior" that Bergmayer is alluding to is AT&T's newly announced rules on how its subscribers can use FaceTime's video call service. Last week, the network released a statement confirming that users on its upcoming Mobile Share plan can run FaceTime over its cellular network. But other plans still require Wi-Fi to use the video service.

Back in June, Apple announced that its latest mobile operating system, iOS 6, would allow users to carry out FaceTime calls through a data network in addition to Wi-Fi. Questions were raised about how much network data this feature would eat up, along with speculation that AT&T may charge its iPhone users for running the video chat feature over its cellular network.

Despite there being no extra cost to use FaceTime, the fact that some AT&T subscribers can use it over their cellular network while others can't could prove problematic with FCC rules, according to Public Knowledge.

"By blocking FaceTime for many of its customers, AT&T is violating the FCC's Open Internet rules," Bergmayer wrote. "These rules state that mobile providers shall not 'block applications that compete with the provider's voice or video telephony services.' Although carriers are permitted to engage in 'reasonable network management,' there is no technical reason why one data plan should be able to access FaceTime, and another not."

AT&T spokesman Mark Siegel told CNET that the company doesn't believe its plan is breaking the FCC's rules. "FaceTime is available to all of our customers today over Wi-Fi, and we're now expanding its availability even further as an added benefit of our new Mobile Share data plans," he said.

Updated at 8:20 p.m. PT with comment from AT&T spokesman Mark Siegel.