d States, CableLabs has specified its own middle- ware system called OpenCable Applications Platform (OCAP), which is based on DVB-MHP. ISDB Standards ISDB is the DTV and DAB format that Japan has created to allow radio and television stations there to convert to digital. ISDB is maintained by the Association of Radio Industries and Businesses (ARIB; www.arib.or.jp). ARIB is a standards organization in Japan, designated as the center of promotion the efficient use of the radio spectrum and frequency change support. ISDB incorporates several standards: ISDB-S (digital satellite TV)-ARIB developed the ISDB-S standards to meet a number of requirements Japanese broadcasters were asking for, including HDTV capability, interactive services, network access, and effec- tive frequency utilization. ISDB-S, operating in the 12GHz band, uses PSK modulation. ISDB-S allows 51Mbps to be transmitted through a single tran- sponder, making it 1.5 times more efficient than DVB-S, which can handle a bitstream of approximately only 34Mbps. This means the ISDB-S system can carry two HDTV channels using one transponder, along with other independent audio and data. ISDB-S was commercially launched in 2000 and today is used by several service providers. ISDB-T and ISDB-Tsb (terrestrial)-In the 1980s, Japan started research on and development of a completely digital system that led to the introduc- tion of ISDB. ISDB-T began commercial operation in Japan in December 2003. ISDB-T specifies OFDM transmission with one of four modulation schemes: QPSK, DQPSK, 16-QAM, or 64-QAM. With ISDB-T, an audio pro- gram and TV for both fixed and mobile reception can be carried in the same multiplex. For example, ISDB-T can transmit three SDTV streams in one channel or carry an HDTV and a mobile phone channel in the same 6MHz usually reserved for TV transmission. The combination of services can be changed at any time, as can the modulation schemes. ISDB-T can support HDTV on moving vehicles at over 62 mph (100 kph), and it can be received on mobile phone