cable television vs telecasting

cable television and telecasting both are nouns.

Word	Noun	Adjective	Verb	Adverb
cable television	Yes	No	No	No
telecasting	Yes	No	No	No

As nouns, telecasting is a hypernym of cable television; that is, telecasting is a word with a broader meaning than cable television:

cable television: television that is transmitted over cable directly to the receiver
telecasting: broadcasting visual images of stationary or moving objects

Other hypernyms of cable television include television, TV, video.

cable television (noun)	telecasting (noun)
a television system that transmits over cables	broadcasting visual images of stationary or moving objects
television that is transmitted over cable directly to the receiver