In the US, channels can be broken down into the following categories:
1) "air" networks (NBC, ABC, CBS, FOX, UPN, WB, independents)
2) public television (PBS)
3) "basic" cable (ESPN, Sci-Fi, TBS, USA, Bravo, etc)
4) "premium" cable (HBO, Showtime, Starz)
Channels in categories 1+2 are...