Comcast Corp has signed up CBS Corp along with 17 more cable networks to participate in the cable company's trial to make more television shows available to its subscribers on the Web.

CBS will be the first broadcast network to take part in trial to show both current and older shows in the On Demand Online program, which will begin a technical trial with about 5,000 U.S. customers in the coming weeks.

CBS is also the only broadcast network not to participate in, the popular TV show site backed by News Corp, NBC Universal and Walt Disney Co.

Comcast also said on Tuesday it is partnering with Cablevision Systems Corp's Rainbow Media, Scripps Networks Interactive, AETN, MGM Impact and BBC to bring content from 17 more cable networks.

TV shows like The Prisoner, Bridezillas, Keeping up with the Kardashians will be available with additional content like AMC's Mad Men and Breaking Ban planned for the coming months.

The latest partnership announcements come after Comcast and Time Warner Inc announced their TV Everywhere project, which would make more TV programs available online to people who subscribe to Comcast's cable TV service.

Comcast will run the shows on its websites, and

Broadcasters, cable operators and other programmers are trying to come up with ways to make TV shows and other content available online because more people are spending their time on the Web than ever before.

At the same time, they are trying to make sure that they do not gut their existing businesses by giving away content on the Internet or letting it get stolen and redistributed by digital pirates.

At stake are billions of dollars in advertising revenue as well as lucrative partnership agreements the various companies have with each other. They are trying to make the transition to the Internet to avoid similar pitfalls that the newspaper and music businesses have encountered there.

CBS shares rose 25 cents, or 4.18 percent, to $6.23 on the New York Stock Exchange. Comcast closed up 4 cents, or 0.3 percent, at $13.56 on Nasdaq.

(Reporting by Robert MacMillan and Yinka Adegoke; Editing by Derek Caney)