AT&T is defending its decision to limit the use of Apple's video chat feature, FaceTime, to its Mobile Share data plans by saying that the limitation does not violate the FCC's net neutrality rules. The company wrote in a blog post on Wednesday that some groups had "another knee-jerk reaction" to AT&T's limitation, but the company argues that its decision meets all FCC requirements.

Last Friday, AT&T issued a statement confirming that the carrier wouldn't charge extra for the use of FaceTime over 3G like many had suspected. However, the company did say that customers who want to use the iPhone video chat feature would be required to subscribe to one of AT&T's new Mobile Share data plans—AT&T's version of a shared data pool that can be used across multiple devices.

The catch for users is two-fold. When we covered AT&T's plans in July, we noted that the savings were not particularly great for many users, particularly the solo tablet-and-smartphone user. As such, it doesn't make much sense for those users to pay extra for a different plan just so they can use FaceTime. More importantly, switching over to the Mobile Share data plan would force many data users who are currently subscribing to grandfathered data plans to give up their unlimited data. AT&T has long said that it would allow unlimited data subscribers to continue using their plans (which are no longer offered to new customers) as long as they didn't change their subscriptions, but those users won't be able to use FaceTime over their cellular connection unless they make that change.

And that's just the beginning. A number of consumer groups immediately reacted to the announcement by saying AT&T's decision violated FCC's Open Internet rules by placing a limitation on the video calling feature. "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," Public Knowledge Senior Staff Attorney John Bergmayer said in a statement.

But AT&T argues that's not the case at all, because the FCC only requires service providers to be transparent about their network management practices, and prohibits providers from blocking applications that compete with the provider's voice or telephony services.

"AT&T’s plans for FaceTime will not violate either requirement. Our policies regarding FaceTime will be fully transparent to all consumers, and no one has argued to the contrary. There is no transparency issue here," AT&T Senior VP of Regulations Bob Quinn wrote on Wednesday.

"Nor is there a blocking issue," Quinn continued. "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. 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, and there are several video chat apps available in the various app stores serving particular operating systems. (I won’t name any of them for fear that I will be accused by these same groups of discriminating in favor of those apps. But just go to your app store on your device and type 'video chat.') Therefore, there is no net neutrality violation."

AT&T argues that customers have always used and may continue to use FaceTime over WiFi without restriction—the company is just broadening customers' ability to use FaceTime by allowing its use over the Mobile Share data plans.

But the company's arguments aren't likely to make consumers or consumer groups feel any better. In an e-mailed statement on Wednesday morning, Free Press research director S. Derek Turner argued that AT&T's defense doesn't hold up.

"AT&T is inventing words that are not in the FCC's rules in a weak attempt to justify its blocking of FaceTime," Turner said. "There is simply nothing in the rules that distinguishes 'preloaded' applications from 'downloaded' applications. It is interesting to see AT&T try this line of defense, as it is tacitly admitting that it is both blocking FaceTime and that the app does in fact compete with its own offerings. FaceTime allows people to reduce their use of voice services, but AT&T is making you buy unlimited voice in order to use FaceTime over mobile. AT&T is trying to invent a loophole in the rules, but this kind of anti-consumer behavior is the exact thing the FCC's protections are designed to prohibit."

Public Knowledge also issued a new response to AT&T's statement. "The FCC's Open Internet rules do not distinguish between pre-loaded and downloaded apps. They prevent carriers from blocking certain kinds of apps--period. 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," Bergmayer wrote on Wednesday.

Free Press is currently running a petition to stop AT&T's "latest attack on net neutrality."