HALLOWELL (AP) — Maine has become the first state in northern New England to sign off on the $1.5 billion sale of FairPoint Communications to Illinois-based Consolidated Communications.

The Maine Public Utilities Commission voted unanimously in favor of the deal Wednesday after Consolidated agreed to invest at least $52.2 million in its infrastructure in Maine. A final order is expected in the next couple of weeks.

Public Advocate Tim Schneider said the deal is good for Maine because the network that’s being acquired by Consolidated serves as the backbone for communications across the state.

“It’s good for the communication networks of the state as a whole,” he said.

The negotiated agreement calls for $17.4 million of annual investments for three years starting in 2018, mostly focusing on expanding and upgrading broadband networks.

Regulators in Vermont and New Hampshire still have to vote. The companies hope to win remaining regulatory approvals and complete the sale this summer.

Consolidated announced plans last year to buy FairPoint. Under the agreement, Consolidated will assume FairPoint’s debt and offer dividends to stockholders.

Regulators sought to avoid repeating mistakes after FairPoint’s acquisition of Verizon’s landline assets in northern New England was fraught with problems.

FairPoint struggled with debt, declining landline accounts and customer service problems before filing for bankruptcy, from which it emerged in 2011. Unionized workers led a four-month strike against FairPoint in late 2014 and early 2015.

Workers are taking a wait-and-see approach about Consolidated but remain hopeful that things will be better than under FairPoint, said Pete McLaughlin, business manager of International Brotherhood of Electrical Workers Local 2327.