Cablevision also said more that one-half of its high-speed Internet customers had signed up for the service. The Cablevision results indicate that cable broadband telephoning is cutting into traditional landline telephone services at a rapid rate.
"Optimum Voice brought competition to a market that had historically been dominated by high-priced monopoly phone companies, and offered consumers a reliable flat-rate voice product that included all the popular calling features with no additional charges or hidden fees," said Tom Rutledge, Cablevision's chief operating officer, in a statement.
Rutledge said the favorable response to Optimum Voice -- primarily a residential service -- positions the company well to move into the VoIP business and voice data services market.
The Optimum Voice service carries a flat monthly fee of $34.95, which includes voicemail, call waiting, caller ID, 411 directory assistance and other features.