The licensing venture is a departure for cable companies that typically run their systems on company-specific set-top boxes.
Mark Hess, senior vice president of business and industry affairs for Comcast's chief technology officer, Tony Werner, said the goal is to speed new products and help cable peers.
He described RDK as a "collection of software" that Comcast engineers "dreamed up." More users for RDK also will help debug the software.
Matt Zelesko, senior vice president at Time Warner Cable, said the licensing should "drive collaboration across the [cable] industry."
The venture was formed, he said, so that one company did not control the RDK software. The joint venture is called RDK Management L.L.C., and the software would be licensed free.
Analysts have praised the X1 platform, and Comcast believes it is a big leap forward in competing with online video providers. X1 allows TV subscribers to personalize their TV experience and tap into Comcast's huge entertainment information database.
Comcast, which employs about 1,000 software engineers, designed some RDK components and used off-the-shelf software for other components.
Time Warner Cable does not yet offer an X1-like channel guide and platform. Zelesko said the New York company could roll the technology out with new set-top boxes in 2014.
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