A controller in a CATV converter provides three operating modes comprising: (1) a family viewing mode in which conversion of selected channels is blocked; (2) an enter access code mode for selecting the channels to be blocked from family viewing; and (3) a parental control mode in which all channels...http://www.google.com.au/patents/US4718107?utm_source=gb-gplus-sharePatent US4718107 - Parental control for CATV converters
