AT&T's $48.5 billion purchase of DirecTV is a done deal, as the Federal Communications Commission today announced that it has voted to approve the merger. After the vote, AT&T announced that it has completed the acquisition.

The FCC imposed conditions on the acquisition, saying they ensure the combination will be in the public interest. AT&T will become the largest pay-TV company in the nation with about 26 million subscribers, jumping ahead of Comcast.

"As part of the merger, AT&T-DirecTV will be required to expand its deployment of high-speed, fiber optic broadband Internet access service to 12.5 million customer locations as well as to E-rate eligible schools and libraries," the FCC's announcement said. (The federal E-rate program provides discounts on Internet service. AT&T will also have to provide discounted broadband to low-income customers.)

AT&T had proposed the fiber build condition itself, though it has said the total number of planned fiber connections is just two million more than the amount it would have built even if the merger had not been approved.

The FCC's announcement came three days after Chairman Tom Wheeler proposed approval. As previously reported, AT&T will be barred from exempting its own online video services from home Internet data caps that are applied to competitors. AT&T will also be required to submit its network interconnection agreements to the FCC so the commission can determine whether the company is "denying or impeding access to its networks in anticompetitive ways through the terms of these agreements."

AT&T will have to follow the conditions for four years after the merger closes. To ensure compliance, AT&T must "retain both an internal company compliance officer and an independent, external compliance officer that will report and monitor, respectively, the combined entity’s compliance with all conditions of the merger," the FCC said.

The FCC's vote was taken behind closed doors. Michael O'Rielly, one of two Republicans on the Democratic-majority commission, criticized Wheeler for making AT&T wait so long. AT&T announced the merger agreement with DirecTV more than a year ago.