You left the Matrix off.. Some of them you can't do that some you can.
Did you select CABLE on the matrix box?
Finally.. When cable first came out TV's had like 61 Channels (2-62) and cable often had 100 or more so you had to have a "Set Top Box" to be able to see all the cable channels.. One per television.
Well over the years some TV makers (not all) put QAM detectors in the TV with the ability to tune 100 channels or more So you could simply put in a splitter and have cable in multiple rooms, without paying an additional per set fee.
SOME cable companies (I Will not name since I'm not sure) are getting nostalagic for the old days when you paid more for additional TV's (You can also say they are getting Greedy, more on that later) So they have gone to encrypting the signal so you once again need a set top box for every tv.
1,000/year for Television (Common size of bill) and they want MORE MORE MORE. Greedy legitimates need a slap down far as I am concerned.