     7   6   5   4   3   2   1   0   7   6   5   4   3   2   1   0   7   6   5   4   3   2   1   0   7   6   5   4   3   2   1   0
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00 | Index+1, 0=invalid            | Length                        | 0x00                          | 0x00                          |
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04 | Message, 64 x ASCII, 0-padded                                                                                              ...
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40  ...                                                                                                                            |
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