AT&T Wednesday confirmed that it will block any use of the iOS FaceTime app across its cellular networks, except for customers who pay for a premium subscription plan.

Previously, the FaceTime videoconfencing app worked only over Wi-Fi networks. But with the forthcoming release of iOS6, expected out in late September or early October, Apple has upgraded FaceTime--which runs on iPhone 4 or later, iPad 2 or later, and iPod touch 4th generation or later--to overcome that limitation, allowing it to also work over cellular networks.

AT&T had already announced that, as with other smartphone services that consume extra cellular network bandwidth, it might charge extra--above its standard data rates--for cellular FaceTime use.

In response to recent criticism over that decision, AT&T officials have said they're not violating relevant Federal Communications Commission regulations, which require carriers to be transparent about their practices and to not block competitive services from their cellular networks. Rather, AT&T is simply applying "reasonable restrictions" on bandwidth-hungry apps, said AT&T chief privacy officer Bob Quinn, who also leads AT&T's federal regulatory group, which handles all regulatory matters for the company that involve the FCC.

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Furthermore, according to AT&T, FCC regulations simply don't cover preloaded apps such as FaceTime. "The FCC's net neutrality rules do not regulate the availability to customers of applications that are preloaded on phones. Indeed, the rules do not require that providers make available any preloaded apps," Quinn said in a blog post. "Rather, they address whether customers are able to download apps that compete with our voice or video telephony services. AT&T does not restrict customers from downloading any such lawful applications. ... Therefore, there is no net neutrality violation."

But many legal experts have criticized AT&T's plans, saying they will indeed place the company in violation of FCC net neutrality regulations. "The FCC's Open Internet rules do not distinguish between preloaded and downloaded apps. They prevent carriers from blocking certain kinds of apps--period," said John Bergmayer, a senior staff attorney at Public Knowledge--a non-profit Washington, D.C.-based public interest group that focuses on Internet and telecommunications laws--in a statement. "AT&T is blocking FaceTime for all of its iPhone customers who do not subscribe to its premium 'Mobile Shared' plans, and this runs afoul of the rules."

AT&T's reasoning also drew criticism from S. Derek Turner, research director for media and technology watchdog Free Press. "AT&T is inventing words that are not in the FCC's rules in a weak attempt to justify its blocking of FaceTime," he said in a statement, noting that the word "preloaded" appears nowhere in the FCC's nearly 200-page Open Internet Order. "The FCC's rules are crystal clear: AT&T is not permitted to block voice or video telephony applications that compete with its own services. There is simply nothing in the rules that distinguishes 'preloaded' applications from 'downloaded' applications."

According to Bergmayer, apps such as FaceTime compete directly with AT&T's own offerings. "Many people use apps like FaceTime, Skype, and ooVoo instead of making voice calls. In many respects these apps are more convenient than traditional calling. And by using these apps, consumers can save money on international calling charges, conference call services, and in other ways," he said. "There's no doubt that these apps are a competitive threat to AT&T's voice service. But as the FCC made clear in its Open Internet rules, mobile providers must compete with these new services fair and square, and not by engaging in discriminatory behavior."

On a related note, for users who are worried about running afoul of providers' data caps--when they do offer cellular network access to apps such as FaceTime--Apple has added features to iOS 6 that allow users to prevent apps from going cellular. Beta versions of iOS6 have featured a new "Wi-Fi Plus Cellular" setting--tagline: "Allow apps having trouble with Wi-Fi to use cellular data"--that allows users to block apps from using a cellular network altogether, or to individually allow or deny such usage for a handful of apps, including iCloud documents, iTunes, and FaceTime.

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