Two television networks announced deals Monday that will allow pay TV subscribers to watch some of their most popular prime-time shows shortly after they air, carrying the promise that many more viewers may no longer be at the mercy of broadcast schedules.

Cable giant Comcast Corp. struck an agreement with CBS that will let cable subscribers with digital service order the top-rated “CSI: Crime Scene Investigation,” “Survivor,” “The Amazing Race” and “NCIS.” Viewers will pay 99 cents an episode through their video-on-demand cable service.

Separately, DirecTV Group Inc. and NBC Universal Inc. struck a similar accord enabling satellite subscribers with new digital video recording boxes to order for the same price some of the network’s prime-time programs, including “The Office,” “Law and Order: Special Victims Unit” and “Law and Order: Criminal Intent.”

Although viewers who own personal video recorders such as TiVos or VCRs can record their favorite shows now, the two deals are unique in that they make TV-on-demand available to a broader number of viewers. It also lets customers pay for shows on an a la carte basis.

Both deals are the first of what are expected to be numerous similar arrangements. They mark the latest examples of how technology is altering the television experience and the traditional network business.

“For 50 years, TV has been a passive medium,” said David Zaslav, president of NBC Universal’s cable group, which includes networks USA and Bravo, whose programming is also part of the DirecTV deal. “But consumers want more choice and more convenience. All the signals are there of a meaningful change in how people watch television.”