Jul. 31--As the company showed strong customer growth in a number of multi-media categories, Cablevision Systems Corp. reported Thursday that second-quarter net income sank 70 percent to $98.3 million but revenue increased 9.2 percent to $1.71 billion for the period ending June 30.

Net income in the second quarter last year, including a one-time gain from an asset sale, was $317.4 million on revenue of $1.56 billion.

Consolidated operating income, a closely watched measure of Cablevision's performance, rose 43.6 percent to $299.3 million.

In response to the earnings news, Cablevision shares soared 13 percent in morning trading, rising to $23.93.

Revenue for the quarter was above analysts expectations of $1.68 billion, according to a poll by Thomson Financial. Cablevision said the higher than expected revenue growth was led by telecom, Rainbow programming and Madison Square Garden groups.

Cablevision exceeded analysts estimates of its growth in the quarter for basic video, digital video, high speed internet and telephone service.

Per-share income of 33 cents beat analysts' estimate of 13 cents, while operating cash flow, adjusted for one-time and other costs, jumped to $602.6 million from $508.5 million a year ago.

Telecom services, including its Optimum Voice, rose 9.2 percent to $1.3 billion, followed by cable TV, which saw a 9 percent increase to $1.24 billion.

The company said digital video subscriber growth in its iO Interactive Optimum service was up by 120,000 customers, or 4.5 percent. During the quarter, the company shifted around a dozen popular cable channels to the digital service, and offered customers a year's free subscription and a year's free use of a cable box.

Some subscribers argued the move amounted to a price increase, saying they would eventually have to pay for channels they received as part of basic cable, and that they were required to pay for multiple boxes beyond the single free one for homes with second or third TVs. Some also said the company's representatives told them the transition was part of the FCC's mandatory transition to digital TV signals. Cablevision said the move was aimed at freeing up bandwidth space by shifting some analog signals to digital.

Cablevision this week acquired 97 percent of Newsday from Tribune Co. for $650 million. Thursday's earnings report did not include any Newsday operations.