* Highest subscriber adds in internet business in 6 yrs
* Cable communications business rev up 5.4 pct
* NBC Universal revenue misses, but profit boosts
* Shares rise as much as 2.6 pct (Adds conference call comment, analyst comment; updates shares)
July 22 (Reuters) - Comcast Corp's quarterly profit beat estimates as its high-speed Internet business added the most number of customers in six years and profitability improved at NBC Universal.
The largest U.S. cable operator's shares rose as much as 2.6 percent on Tuesday.
Comcast added 203,000 net high-speed Internet customers in the second quarter ended June 30, higher than the 161,000 additions analysts expected, according to market research firm StreetAccount.
A reasonable estimate for the timing of a shareholder vote on Comcast's Time Warner Cable Inc (TWC) deal would be in the fall, Chief Financial Officer Michael Angelakis said.
Comcast is seeking regulatory approval for its $45.2 billion bid for TWC, which will help it pick up customers in New York and Los Angeles and extend its X1 cable TV-cum-Internet service to those cities.
The company has also been building up its WiFi network, aiming to have 8 million hot spots in 19 of the 30 largest U.S. cities this year. TWC has 34,000 hot spots.
The TWC bid has sparked off consolidation efforts in the media and telecoms industry, as demand grows for broadband Internet and streaming video and music content.
Telecom company AT&T Inc, which hardly produces programs, said it would buy satellite TV company DirecTV for $48.5 billion.
SoftBank Corp's arguments for buying T-Mobile US Inc now hinge on creating a scaled counterpoint to Comcast, while Twenty-First Century Fox Inc's bid for Time Warner Inc is about matching Comcast's leverage, MoffettNathanson analyst Craig Moffett said.
"The DOJ and/or FCC will be under tremendous pressure to block at least one of the mega-deals, lest they be viewed as being asleep at the switch."
Comcast's cable business, which also houses the Internet business, lost 144,000 net video subscribers in the quarter - more than the 123,000 expected.
However, strong Internet business and services sales growth helped revenue grow 5.4 percent to $11.03 billion.
Revenue at NBC Universal, the media and entertainment company Comcast bought last year, inched up 0.3 percent to $6.02 billion.
But operating cash flow jumped 20 percent due to broadcast television and filmed entertainment, analysts at JPMorgan, Jefferies and Brean Capital said.
Net income attributable to Comcast rose 15 percent to $1.99 billion, or 76 cents per share. Excluding items, it earned 75 cents per share, higher than the average analysts' estimate of 72 cents, according to Thomson Reuters I/B/E/S.
Revenue rose 3.5 percent to $16.84 billion - below an estimated $16.95 billion.
Comcast shares were up 1.8 percent at $54.80 in afternoon trading on the Nasdaq. It gained 3.6 percent this year through Monday's close. (Additional reporting by Liana Baker; Editing by Savio D'Souza and Joyjeet Das)