NEW YORK, Sept 9 - Comcast Corp and Time Warner Cable Inc said on Tuesday they are confident of picking up a substantial number of new customers from the digital television transition early next year. The two largest U.S. cable operators said they see the government-mandated switch-over to digital TV from analog signals on Feb. 17 as an opportunity to win new subscribers. Comcast Chief Operating Officer Steve Burke said 2 million to 3 million non-pay-TV homes in Comcast's area will not be able to receive digital TV signals over-the-air, forcing them to consider options including pay-TV provider Comcast. "It's not out of the question that we could gain a substantial number of new customers through the transition," said Burke, speaking at a Merrill Lynch investor conference. Comcast, which has more than 24 million subscribers, will be marketing aggressively to existing customers to assure them that they will continue to receive TV signals after the transmission switch, according to Burke. He said the company is also offering a low-priced broadcast-only service as well as trying to sell its high-speed Internet and phone services to these customers. Comcast said the early investment in going all-digital could be around $800 million in capital expenditure, including the supply of an additional 25 million incremental set top boxes and digital converters. "We hope to get the majority of the company done in the next 12 to 18 months," said Burke, who said the investment would not have a significant impact on the company's free cash flow projections. On Monday, Wilmington, North Carolina, became the first U.S. TV market to switch to all-digital television broadcast as a test by the U.S. Federal Communications Commission ahead of the February deadline. Wilmington's cable television is provided by Time Warner Cable. "We're going to learn a lot a Wilmington," said Landell Hobbs, chief operating officer of Time Warner Cable. Hobbs, who was also speaking at the Merrill Lynch investor conference, said his company had already seen early migration to its service following the switch-over in Wilmington which could potentially replicated nationally. He said there are around 4 million homes in the Time Warner Cable area which receive analog TV signals over the air. "There's definitely an opportunity," said Hobbs, also pointing to the potential of bundling other services like phone and high speed Internet.