The following is from the fcc.gov website. Note that this applies to broadcast TV and radio and not to cable or any other subscription service:
Obscene Broadcasts Are Prohibited at All Times
Obscene material is not protected by the First Amendment to the Constitution and cannot be broadcast at any time. The Supreme Court has established that, to be obscene, material must meet a three-pronged test:
•An average person, applying contemporary community standards, must find that the material, as a whole, appeals to the prurient interest;
•The material must depict or describe, in a patently offensive way, sexual conduct specifically defined by applicable law; and
•The material, taken as a whole, must lack serious literary, artistic, political, or scientific value.
Indecent Broadcast Restrictions
The FCC has defined broadcast indecency as “language or material that, in context, depicts or describes, in terms patently offensive as measured by contemporary community standards for the broadcast medium, sexual or excretory organs or activities.” Indecent programming contains patently offensive sexual or excretory material that does not rise to the level of obscenity.
The courts have held that indecent material is protected by the First Amendment and cannot be banned entirely. It may, however, be restricted in order to avoid its broadcast during times of the day when there is a reasonable risk that children may be in the audience.
Consistent with a federal indecency statute and federal court decisions interpreting the statute, the Commission adopted a rule that broadcasts -- both on television and radio -- that fit within the indecency definition and that are aired between 6:00 a.m. and 10:00 p.m. are prohibited and subject to indecency enforcement action.
Profane Broadcast Restrictions
The FCC has defined profanity as “including language so grossly offensive to members of the public who actually hear it as to amount to a nuisance.”
Like indecency, profane speech is prohibited on broadcast radio and television between the hours of 6 a.m. and 10 p.m.
George Carlin also did a routine including the words you can't say on TV but I'll go with the FCC even though it's not applicable here.
