Cox and NBC started another test in which TV commercials of traditional TV will resemble those on the Internet -- commercials will be continually refreshed with no fast-forwarding function.

The trial, which was originally conceived months ago, is working with a large, unnamed advertiser for Cox video-on-demand service in its Phoenix area system. Two NBC shows are in the test: NBC's "The Office" and USA Network's "Monk."

Both shows are available through Cox's MyPrimetime, a category of its overall On Demand service, which provides access to network shows starting the day after they air.

During the trial, up to four ads and/or promos in both programs are refreshed several times per week, including ads at the beginning of the program as well as ads within the program. This is the second such test of Cox's "dynamic ad insertion" system. A trial earlier this year was done in Kansas. It tested dynamic ad insertion with Cox-owned Travel Channel for its video-on-demand content.

"The capabilities for dynamic ad insertion have been proven, and there is significant value for the entire cable and advertising ecosystem -- something we expect to confirm during the current trial with NBC Universal," said David Porter, vice president of advertising product development for Cox Media, the ad-selling division of Cox Communications, which represents 23 U.S. markets.

Recently, Cox announced it was adding "The Office", "30 Rock," "Community," "Parks and Recreation," "Mercy" and "Heroes" to its on-demand service.

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