The CAT provides information on the used Conditional Access System(s),the PID of the corresponding EMM (Entitlement Management Messages) flow and any parameters for these systems. The maximum size of the CAT is 4096 bytes.
TR 101 290
  • The repetition rate must be less than 0.5 seconds.
  • The time between receiving the last byte of the section and the first byte of the next section should be at least 25 ms.
  • The Scrambling Control must have the binary value '00 ' ( umscrambled )
  • Descriptors

    name bits description
    Table ID 8 Indicates to which table this section belongs, in this case CAT (0x01)
    section_syntax_indicator 1 Indicates whether a sub-table structure including CRC check is used.
    0 1 always binary value '0'
    Reserved 2 always binary value '11'
    Section length 12 The length of the section in bytes. This length starts immediately after this field and includes the CRC.
    reserved 18 always binary value '111111111111111111'
    version_number 5 value between 0 to 31.
    A higher value indicates that the information has changed.
    current_next_indicator 1 This is to indicate whether a section is 'valid now' or 'valid in future'
    section_number 8 Value between 0x00 - 0xFF. Used to indicate the sections of a table. Up to 256 sections
    last_section_number 8 The number of the last section, so the receiver know when the table is completely received.
    Descriptor Loop
    CRC_32 32 Cyclic redundancy check