Television is a device that allows people to view broadcast plays, news, drama and comedy. The Television Set was invented in 1925 when Scottish inventor John Logie Baird utilised a Nipkow Disc and assorted mechanical parts. The device did not bear any relation to the Television set of today (which was invented by wikipedia:Marconi EMI).
By the early 1950s the sets were already highly developed, although still early in their development. The Wire tried to regain a physical body by using the Alexandra Palace Television Transmission, although the Doctor managed to trap her in a Video Cassette. (DW: The Idiot's Lantern)
In the far future, television was still a popular past-time, though violent television was much more common, such as on Varos and in the Fourth Great and Bountiful Human Empire. (DW: Vengeance on Varos and Bad Wolf) Other Human nations liked to watch the shows from old Earth, such as the New Earth Republic. (DW: Synthespians™)