Hawaiian Telcom said today a decline in the company’s third-quarter earnings was due mostly to an increase in costs associated with the expansion of its broadband network.

The state’s largest phone company reported net income of $5.6 million, or 52 cents a share, in the July-to-September quarter, down from $7.4 million, or 68 cents a share, in the same period a year earlier.

Revenue totaled $96.6 million in the third quarter, down slightly from $97.0 million a year earlier. Revenue growth in video, high-speed internet and equipment sales was offset by a 5.6 percent decline in access lines, also known as land lines, the company reported.

Revenue from the company’s video service, which launched in July 2011, rose to $1.53 million in the third quarter from $1.04 million in the second quarter. There were 8,444 subscribers to the video service as of Sept. 30, up from 6,354 three months earlier.

“Our quarterly results continue to show positive momentum in our key next-generation services,” said Eric Yeaman, Hawaiian Telcom’s president and chief executive officer. “The success of Hawaiian Telcom TV continues to be a strong catalyst driving our second consecutive quarter of sequential growth in consumer revenues.”

Hawaiian Telcom’s shares were up 15 cents at $16.65 in late trading on the Nasdaq Global Market.