A modular interface (12a) allows new functionalities to be added to a television receiver (12). A module (20, 100, 200, 300) can be added to the television receiver (12) through the interface (12a) that will enable additional functionalities on the television. The interface (12a) allows copy protection of digital video and audio content by incorporating HDCP technology, thereby also allowing the manufacturer of the interface (12a) to control the access to the interface (12a).