In what could finally be the showcase proponents of interactive television programming have sought for the last five years, Comcast is slated to begin a groundbreaking pilot launch of ITV services from several cable networks in Baltimore later this year, sources said.

The move marks the first concentrated effort by a cable operator to provide enhanced TV from more than one programmer.

This broad embrace from Comcast, the largest multiple system operator in the country, and programmers that have already signed on such as CNN, GSN and HSN, validates the enthusiasm that ITV pioneers have expressed over the potential impact of interactivity on the television model. It also represents a step toward the cable sector catching up to its satellite competitors, which have already rolled out interactive services.

Proponents argue that ITV offers great revenue-generating potential, as interactive advertisements can command premium rates and interactive programming has proven to keep viewers more engaged.

The Baltimore test will make real-time participatory viewing enhancements available to the users involved in the test via their existing remote control without changing the channel. For example, among the features of “one-screen” capability, viewers will be able to click a button while watching CNN to get additional information on a news story being reported. They may also be able to access weather reports from The Weather Channel.

If the Baltimore tryout is successful, Comcast would be in the position to seamlessly replicate the offering in other markets as the multiple system operator did with its local video-on-demand experiments.

Comcast is keeping details of the Baltimore experiment quiet and would not characterize it as a “deployment.” Comcast spokeswoman Jenni Moyer said the company has offered ITV trivia from Buzztime as a market trial and that if there are any additional ITV efforts in the market they would only be a “test.”

“There are no commercial deployments planned,” Ms. Moyer said. “Just because we trial something doesn’t mean it’s going to get deployed commercially. We do trials all the time.”

However, sources insist that if the Baltimore test goes well, Comcast will start with a soft launch later this year and move to a broader commercial rollout there early next year. GoldPocket Interactive would provide the technological underpinning for the rollout. GoldPocket CEO Scott Newnam would not comment on the Baltimore launch.

To date, ITV in general has enjoyed only minimal deployment. The most significant one-screen ITV work has occurred in Hawaii, since Oceanic Time Warner Cable introduced one-screen interactivity with GSN there last year.

Now, many programmers and operators are coming to the party. In addition to GSN, CNN and HSN, The Weather Channel and one of the A&E Networks-A&E or History Channel-are also likely to be involved. ESPN said it’s talking to Comcast about ITV opportunities but is not involved in any specific tests. CNN, GSN, HSN and The Weather Channel all declined to comment on the Baltimore project.

Comcast has also been in talks with broadcast and cable networks about potential ITV content. Interactivity fits more naturally with some networks, like GSN, than others, such as, say, Hallmark Channel. Some networks still need to be convinced it’s worth their while to invest in the creative power and tools to make programming interactive.

Still, “The industry is moving forward in ITV in a big way,” said Channing Dawson, senior VP emerging media at Scripps Networks, which owns Food Network, HGTV, DIY, Fine Living and GAC. He added, however, that while Scripps has been invited to take part in the Baltimore experiment, the company does not plan to go forward yet.

A&E wants to deploy ITV with several different distributors next year, according to Jim Turner, VP interactive at A&E Television Networks. “We are seriously evaluating partnering with Comcast,” Mr. Turner said.

Mr. Dawson added that he “doesn’t know anyone who has not been invited.”

“We consider Comcast an important partner, and as we participate with them with VOD, we look forward to a similar ITV participation,” Mr. Turner said.

“The next iteration will be good for the cable operators,” Mr. Dawson added. So far, the cable industry has been beaten to the ITV punch. Both DirecTV and EchoStar have moved aggressively into interactivity this year. And there is more to come. The telcos launching digital video have said they will be able to offer full suites of next-generation services, including VOD, many HD channels and ITV programming.

“You can make money with it,” said Eric Shanks, senior vice president, Advanced Services and Content at DirecTV.

Also, both DirecTV and EchoStar have been aggressive this year in selling interactive commercials. The return on investment “for us is continuing to attract more general advertising to our platform and attract more overall revenue. This is the first year we have attributed any revenue to interactive,” Mr. Shanks said. “Next year I think we will see a really good bounce.”

The success GSN had in Hawaii with Time Warner played a large role in the network’s decision to market nationally its GSNI service earlier this summer.

GSN has been an ITV pioneer because its content is inherently interactive-viewers naturally desire to play along, said John P. Roberts, senior VP interactive entertainment at GSN. Now that other programmers are getting involved, their presence validates that ITV has become more mainstream and could soon reach a tipping point, he said.

“If we were the only network doing this, it wouldn’t be a business. We embrace other networks jumping into the interactive pool,” Mr. Roberts said.

“It is safe to say that ITV is here,” GoldPocket’s Mr. Newnam said.

HSN announced a deal with GoldPocket in March to develop a one-screen ITV application that allows viewers to purchase items from the shopping network via the remote. The application runs in real time along with the network 24 hours a day.

HSN’s John McDevitt, VP finance and business development, said that HSN has been testing its one-screen application and is planning some public launches later this year.

James Glasscock, the director of business development for Turner Broadcasting System, said ITV efforts from Turner-owned networks such as CNN will begin to roll out in the next 12 months. Turner has been active in ITV for some time, including earlier work with now-defunct Wink. The difference now, Mr. Glasscock said, is that operators are asking for the content. “It’s no longer us pushing them, but us partnering with them,” he said.

The Weather Channel is talking to major cable, satellite and telco distributors about its enhanced one-screen ITV application and expects to have a few major deals in place in the next few months, said Lisa Shankle, VP of on-demand TV services for The Weather Channel.

Not all programmers are convinced of the business model. “We are studying it, following it and looking at the best way to get in,” Mr. Dawson said. “We love the idea, but nobody has convinced me there is a business in the short term.”