A year from now, some Spectrum customers in Maine will see their annual bill increase by $90 or more in the wake of the cable giant’s conversion to an all-digital system, which is rolling out in greater Portland next week.

All TVs will require cable boxes to receive Spectrum channels after it begins sending signals digitally. Customers who had been plugging their TVs directly into cable hook-ups will have to get cable boxes, which will be free at first. But after a year, the company will start charging rent for the boxes, which will range from $7.50 to $11.15 a month. That’s on top of any price increases that Spectrum seeks for 2019.

Spectrum has sent letters, emails and run ads on its cable system to alert customers to the change, although some of the notices don’t explicitly state the fees customers will have to pay to rent the boxes.

The conversion began last month in northern Maine, and parts of southern Maine are being converted now, said Andrew Russell, director of communications in the Northeast for Charter Communications, which owns Spectrum. The conversion will begin Tuesday in Portland and on Nov. 13 in South Portland and Cape Elizabeth, with all changeovers complete by the end November, Russell said.

For Don Patriquin of Kennebunk, the Oct. 23 conversion date snuck up on him. He realized he had to convert his TVs when three of the four wouldn’t work that morning.

So he drove to the nearest Spectrum office to get three conversion boxes – one TV already had a cable box but three others hooked directly into the cable connection.

He said the process took hours because he realized that two of the TVs had older coaxial cable connections, rather than HDMI ports, and he had to return to the Spectrum office in Wells to get the correct equipment. It also takes a long time for the cable boxes to boot up, he said, but otherwise the process was relatively easy.

His irritation was compounded by an email from Spectrum saying his billing plan had changed and he would be charged $33 more a month — $11 for each of the new boxes. He eventually got that changed with a call to customer service. Because of the terms of his deal, he will pay $11 more a month for one of the boxes for a year, after which the full charge for all three boxes will kick in.

Russell said the “vast majority” of the cable system’s customers already have a digital connection in their homes, but some might have second television sets that are connected to the cable coming out from a wall, without a cable box. He declined to provide exact numbers of how many Spectrum customers in Maine will need cable boxes.

People who need a digital box can get one by visiting a Spectrum location or by calling the company. Russell said it’s relatively easy to disconnect the direct cable connection to the television, connect it instead to the digital receiver and then connect that to the television. The fee for having Spectrum visit a home to make the connections is $29.99, he said.

The digital cable box will be free to customers for at least a year, Russell said, and longer for those with certain programming packages. Otherwise, the fee will be $7.50 a month for customers who signed up with Spectrum and $11.15 a month for legacy Time-Warner cable packages, he said.

Russell said the switch to digital will free up capacity in its system for internet use and will be used to send more high-definition and other television content.

The Maine Public Advocate’s Office said it has received a handful of complaints since the conversion began in mid-September, most dealing with the higher fees that will be imposed in a year.

“We understand the hardships of an increasing bill,” said Keira Reardon, the consumer adviser in the advocate’s office. However, Maine, like other states, has little oversight over cable companies and what little power it does have deals with issues such as overseeing cable systems’ requests to connect to utility poles.

“We have limited, if any, jurisdiction,” she said.

Her office did look into whether consumers could buy the cable boxes, instead of paying monthly rental fees, but the manufacturer doesn’t sell them directly to consumers, Reardon said.

She and Barry Hobbins, who leads the public advocate’s office, said they’ve heard rumors of bills that will be introduced in the next legislative session to give the state or municipalities, which have individual contracts with cable providers, more power over the cable companies. However, most of those community contracts run for decades, Reardon said. Like the states, towns and cities don’t have a lot of leverage to make changes soon.

But technological advances may allow consumers to gain some power in the relationship. Streaming services now offer programming from over-the-air and cable channels — anyone who watched the World Series on Fox learned that the game was also available, for a fee, on YouTube TV. And another streaming service, Hulu, also offers dozens of broadcast channels as an add-on for its service.

Patriquin said he notices a slightly better picture quality on his one high-definition set because of the digital signal, but no change in the others. Irritating pixelations – where the TV image freezes and then breaks up for a few seconds – continue a they did before the digital conversion, he said.

“When you’re paying $200 a month, it ought to work perfectly,” he said.