While cable broadband providers like Comcast generally dominate telephone firms in broadband subscriber speeds today, Comcast can look in its rearview mirror and see Verizon Communications' very high speed fiber-optic service (FiOS) gaining quickly.

Looking ahead, Comcast unveiled its future weapon -- a modem three times faster than FiOS -- in the battle of broadband high speeds this week at the National Cable and Telecommunications Association meeting in Las Vegas. The modem, developed by the Cable Industry's Cable Television Laboratories, already outpaces Verizon's FiOS product, which boasts download speeds of 50 Mbps.

The cable modem, which could be available in a few years, features a broadband download speed of 150 Mbps, according to media reports. In the Las Vegas demo, a 32-volume copy of the Encyclopedia Britannica and Merriam-Webster's visual dictionary were downloaded in less than four minutes.

"If you look at what just happened, 55 million words, 100,000 articles, more than 22,000 pictures, maps, and more than 400 video clips," Comcast chief executive Brian Roberts said, according to an Associated Press recount of his keynote. "The same download on dial-up would have taken two weeks."

The DOCSIS 3.0 technology ties four cable lines together.

Cable broadband today dominates the high-speed broadband data world with several million subscribers. Verizon has fewer than 400,000 FiOS subscribers and AT&T has even fewer subscribers for its fiber-based broadband service.