For some years, digital pay television services have been accompanied by software applications which are downloaded from the broadcast into the set-top boxes in the living room and executed there. The formats and protocols used for these are proprietary. In 2000, after a long and difficult development process, the DVB Project offered to the world an open standard specification to support the execution of such applications called the Multimedia Home Platform (MHP). It enables digital content providers and broadcast equipment suppliers to address MHP receivers, regardless of the manufacturer of the receiver or the developer of the MHP middleware implementation. Since the completion of version 1.0 of the MHP specification in January 2000, derivative specifications have been produced for non-DVB markets. One such derivative is the Open Cable Application Platform (OCAP) produced by CableLabs for cable TV in the United States. This removes completely those MHP features which are simply not applicable in that market. Other features are replaced with a U.S. equivalent. Extensions have been defined by CableLabs for additional requirements.