HDTV -- already in my cable, or not?

Fran Fruit

Honorable
Mar 13, 2013
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10,510
I'm sure this is a dumb question, but that hasn't stopped me before. Also, please understand I'm not trying to get anything I haven't paid for, but on the other hand I don't want to not get something I'm legally entitled to just because I don't know about it. So here goes: I currently have regular SD programming from Comcast. If I were to sign up for HD programming from them, would they begin sending a different kind of signal to my house, or just enable me to access a signal that's coming in already?
 

Fran Fruit

Honorable
Mar 13, 2013
4
0
10,510


So are you saying that the HD signal *must* be turned on by the cable company, regardless of whether my set top box can receive them?