Digital television system is constitute of the following parts:
- SMS: Subscriber Management System, it is a system on the management function relate to the subscriber.
- DataBase：It is used to save the subscriber data and EMM data.
- SMS Server：it is used to exchange data between SMS and DataBase or CAS, Also it can send entitled data and message automaticlly . The soft should be installed in the computer with the DataBase.
- CAS：Condition Access System, it is used on scrambling and controlling of the Television Program in software methods.
- SCR：Scrambler, for scrambling and controlling of the Television Program in hardware.
- STB：Set Top Box, for the descrambling and watching of the Television Program.
7. SmartCard：for the descrambling and controlling of the Television Program.
