Closed captioning services for live broadcast television

Yes. For live broadcast television, closed captioning is typically provided by specialized real-time captioning vendors that send caption data to the broadcaster’s caption encoder. The captioner may use stenography, voice writing, or increasingly automated speech recognition with human oversight.

Some established providers include:

How the broadcast arrangement works

For a typical live newscast, for example:

TV station → live program audio → captioning provider → caption data → station's caption encoder → broadcast signal → viewer's TV

The FCC's rules specifically recognize real-time captioning vendors and set expectations around accuracy, synchronization, completeness, placement, qualified captioners, technical redundancy, and rapid response to captioning problems.www.law.cornell.edu

The important distinction is that the television station/network remains responsible for complying with the FCC's captioning requirements, even when it contracts the actual captioning work to an outside vendor. The FCC rules also encourage programmers to include performance requirements and quality verification in agreements with captioning vendors.www.law.cornell.edu

If you're looking for vendors specifically for a U.S. local TV station, cable network, or national broadcast network, I can also give you a more comprehensive list of 10–20 providers, with their technologies, geographic coverage, and contact/sales information.