AT&T said Thursday that it will allow all subscribers to access FaceTime on Apple devices, reversing a controversial policy to block the app for certain data plan customers.

The company said that within eight to 10 weeks, the video and voice calling app will be available to subscribers of older unlimited and tiered data plans. In September, AT&T said those customers of the new iPhone 5 or iOS6 wouldn’t have access to FaceTime. The company offered the app only for new Apple device customers who agreed to buy into shared data plans, in which the company bundles together data charges for multiple devices.

AT&T had feared that if too many customers began using FaceTime over its mobile network, it would bog down the system, leading to dropped calls and slow Internet access for all.

“We decided to take this cautious approach for important reasons,” executive vice president Jim Cicconi said in a blog post. “To do otherwise might have risked an adverse impact on the services our customers expect — voice quality in particular — if usage of FaceTime exceeded expectations.”

The move comes after public interest groups filed a formal complaint with federal regulators that AT&T’s practice violated Internet access rules. The Federal Communications Commission prohibits wireless companies from blocking apps that compete with their own voice and video services.

“AT&T cannot block FaceTime based on claims of potential congestion,” said Matt Wood, policy director at Free Press, a public interest group that filed the complaint. “AT&T simply can’t justify blocking an app that competes with its voice and texting services unless customers purchase a more expensive monthly plan that includes an unlimited amount of those very same services.”

The company’s wireless practices have come under recent scrutiny by the FCC, which earlier this week slapped the company with a $700,000 fine for switching customers to monthly data plans. The company, the FCC found, had promised those customers would retain their unlimited plans but were forced to pay into monthly data tiers.

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