47 CFR § 76.921 - Buy-through of other tiers prohibited.
(a) No cable system operator, other than an operator subject to effective competition, may require the subscription to any tier other than the basic service tier as a condition of subscription to video programming offered on a per channel or per program charge basis. A cable operator may, however, require the subscription to one or more tiers of cable programming services as a condition of access to one or more tiers of cable programming services.
(b) A cable operator not subject to effective competition may not discriminate between subscribers to the basic service tier and other subscribers with regard to the rates charged for video programming offered on a per-channel or per-program charge basis.
(c) With respect to cable systems not subject to effective competition, prior to October 5, 2002, the provisions of paragraph (a) of this section shall not apply to any cable system that lacks the capacity to offer basic service and all programming distributed on a per channel or per program basis without also providing other intermediate tiers of service:
(1) By controlling subscriber access to nonbasic channels of service through addressable equipment electronically controlled from a central control point; or
(2) Through the installation, noninstallation, or removal of frequency filters (traps) at the premises of subscribers without other alteration in system configuration or design and without causing degradation in the technical quality of service provided.
(d) With respect to cable systems not subject to effective competition, any retiering of channels or services that is not undertaken in order to accomplish legitimate regulatory, technical, or customer service objectives and that is intended to frustrate or has the effect of frustrating compliance with paragraphs (a) through (c) of this section is prohibited.