I have the AN649 Rev 1.8, it does not mention the DLS service data format when the DSCTy is not DLS/DL+. I need to know the format for other DSCTy type, such as TMC and MOT. Is there any updated release for AN649, or any other document telling these?

 

Regards,

Colman

 

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  • I have read them, but I don't know how the PAD data are related to them!

     

    Colman

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  • colman wrote:

    I have read them, but I don't know how the PAD data are related to them!


    Then I'd recommend to read ETSI EN 300 401, chapter 7.4 Programme Associated Data (PAD).

     

    Best regards,

    Andi

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  • Sorry, I still cannot understand it, below is the first 32 bytes of the payload when DATA_src=1, DSCTy=60 from a response of command 0x84 (GET_SERVICE_DATA). Can you explain how to decode it?

     

     

    74 E0 80 0A 12 86 65 01-F1 FC 5B 14 F1 30 22 4B 
    38 DB 8E DC B6 3F 4F E7-5D 27 DA 3E 20 5C 42 23

    ....

     

    some begins with 0x73, as

    73 70 80 00 12 86 65 00-25 00 01 CC 70 12 84 01
    85 00 00 00 00 CC 15 00-52 61 70 69 64 53 4C 53

    ...

     

    Regards,

    Colman

     

     

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  • colman wrote:

    Sorry, I still cannot understand it, below is the first 32 bytes of the payload when DATA_src=1, DSCTy=60 from a response of command 0x84 (GET_SERVICE_DATA).


    DSCTy=60 means it's MOT.

    The data begins with headers as defined in EN 300 401, 5.3.3 Packet mode - data group level 

     

    Headers.png

     

    So let's decode your first expample data:

     

    74 E0 80 0A 12 86 65 01 F1 FC 5B 14 F1 30 22 4B 38 DB 8E DC B6 3F 4F E7 5D 27 DA 3E 20 5C 42 23
    
    MSC data group header = 74 E0
     01110100 ‭11100000‬
      Extension flag = 0
      CRC Flag = 1
      Segment flag = 1
      User access flag = 1
      Data group type = 0x4 -> MOT body
      Continuity index = 0xE
      Repetition index = 0x0
    
    Session header = 80 0A 12 86 65
     Segment field = 80 0A
      ‭ 10000000 00001010‬
        Last = 1
        Segment number = 0xA (10)
     User access field = 12 86 65
      ‭00010010‬
       Rfa = 0x0
       Transport Id flag = 1
       Length indicator = 0x2
       Transport Id = 0x8665
    
    MSC data group data field = 01 F1 FC 5B 14 F1 30 22 4B 38 DB 8E DC B6 3F 4F E7 5D 27 DA 3E 20 5C 42 23 ...

    -> This (MSC data group data field) now is the MOT data (to be fed to MOT decoder), composed of headers and data according to EN 301 234

     

    First part is according to 5.1.1 Segmentation header

    Mot_segHeader.png

     Segmentation header = 01 F1
       ‭00000001 11110001‬
        Repetition count = 0x0
        Segment size = 0xF1 (241)

     

    Then follows Segment data = FC 5B 14 F1 30 22 4B 38 DB 8E DC B6 3F 4F E7 5D 27 DA 3E 20 5C 42 23 ...

     

    Best regards,

    Andi

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  • I am clear now. Thank you very much!

     

    Colman

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