1

I have not had success with reveng on figuring out how to calculate these CRCs. I successfully figured out another similar CRC from the same author so I'm pretty sure that the first four bytes as shown are not part of the CRC calculation. The algorithm may be non standard. I have access to a lot of but here is a sample.

n/a             calculate CRC16 from these                  CRC16       n/a
----------------------------------------------------------------------------
68 0D 0D 68     73 01 03 09 01 02 04 00 00 41 41 41 41      78 38       16
68 07 07 68     7A 01 0E 03 02 00 00                        C9 78       16     
68 07 07 68     7A 01 0E 03 03 00 7D                        B6 78       16     
68 0B 0B 68     7A 01 26 07 04 01 01 00 00 00 F0            E1 AD       16                                         
68 0B 0B 68     7A 01 26 07 05 15 01 00 00 00 F0            E9 0D       16                                         
68 07 07 68     7A 01 30 03 06 02 94                        AD 7C       16     
68 07 07 68     7A 01 30 03 07 00 EA                        D1 78       16     
68 07 07 68     7A 01 30 03 08 00 F6                        D3 78       16     
68 07 07 68     7A 01 30 03 09 00 CB                        EC 78       16     
68 07 07 68     7A 01 30 03 0A 00 CA                        EB 78       16     
68 07 07 68     7A 01 09 03 0B 00 00                        C7 78       16     
68 07 07 68     7A 01 05 03 0C 00 00                        F9 78       16     
68 07 07 68     7A 01 05 03 0D 00 13                        E8 78       16     
68 07 07 68     7A 01 05 03 0E 00 26                        DB 78       16     
68 07 07 68     7A 01 05 03 0F 00 39                        C6 78       16     
68 07 07 68     7A 01 05 03 10 00 4C                        8D 78       16     
68 07 07 68     7A 01 05 03 11 00 5F                        9C 78       16     
68 07 07 68     7A 01 05 03 12 00 72                        B7 78       16     
68 07 07 68     7A 01 05 03 13 00 85                        42 78       16     
68 07 07 68     7A 01 05 03 14 00 98                        51 78       16     
68 07 07 68     7A 01 05 03 15 00 AB                        60 78       16     
68 07 07 68     7A 01 05 03 16 00 BE                        73 78       16     
68 07 07 68     7A 01 05 03 17 00 D1                        1E 78       16     
68 07 07 68     7A 01 05 03 18 00 E4                        35 78       16     
68 07 07 68     7A 01 05 03 19 00 F7                        24 78       16     
68 07 07 68     7A 01 05 03 1A 01 0A                        DF 7A       16     
68 07 07 68     7A 01 05 03 1B 01 1D                        CA 7A       16     
68 07 07 68     7A 01 05 03 1C 01 30                        E9 7A       16     
68 07 07 68     7A 01 05 03 1D 01 43                        98 7A       16     
68 07 07 68     7A 01 05 03 1E 01 56                        8B 7A       16     
68 07 07 68     7A 01 05 03 1F 01 69                        B6 7A       16     
68 07 07 68     7A 01 05 03 20 01 7C                        DD 7A       16     
68 07 07 68     7A 01 05 03 21 01 8F                        2C 7A       16     
68 07 07 68     7A 01 05 03 22 01 A2                        07 7A       16     
68 07 07 68     7A 01 05 03 23 01 B5                        12 7A       16     
68 07 07 68     7A 01 05 03 24 01 C8                        61 7A       16     
68 07 07 68     7A 01 05 03 25 01 DB                        70 7A       16     
68 07 07 68     7A 01 05 03 26 01 EE                        43 7A       16     
68 07 07 68     7A 01 05 03 27 02 01                        AE 7C       16     
68 07 07 68     7A 01 05 03 28 02 14                        A5 7C       16     
68 07 07 68     7A 01 05 03 29 02 27                        94 7C       16     
68 07 07 68     7A 01 05 03 2A 02 3A                        8F 7C       16     
68 07 07 68     7A 01 05 03 2B 02 4D                        FA 7C       16     
68 07 07 68     7A 01 05 03 2C 02 60                        D9 7C       16     
68 07 07 68     7A 01 05 03 2D 02 73                        C8 7C       16     
68 07 07 68     7A 01 05 03 2E 02 86                        3B 7C       16     
68 07 07 68     7A 01 05 03 2F 02 99                        26 7C       16     
68 07 07 68     7A 01 05 03 30 02 AC                        2D 7C       16     
68 07 07 68     7A 01 05 03 31 02 BF                        3C 7C       16     
68 07 07 68     7A 01 05 03 32 02 D2                        57 7C       16     

EDIT

Here are two groups only incremented by one bit, this was as many as I could 
gather.

73 01 03 09 01 02 04 00 00 31 32 33 34      EA 1C  
73 01 03 09 02 02 04 00 00 31 32 33 34      DA 1C  
73 01 03 09 04 02 04 00 00 31 32 33 34      BA 1C  
73 01 03 09 08 02 04 00 00 31 32 33 34      7A 1C  
73 01 03 09 10 02 04 00 00 31 32 33 34      7A 19  
73 01 03 09 20 02 04 00 00 31 32 33 34      7A 13  
73 01 03 09 40 02 04 00 00 31 32 33 34      7A 07  
73 01 03 09 80 02 04 00 00 31 32 33 34      7A 2F


08 01 83 07 01 00 00 00 40 00 00            2D BE   
08 01 83 07 02 00 00 00 40 00 00            35 BE   
08 01 83 07 04 00 00 00 40 00 00            05 BE   
08 01 83 07 08 00 00 00 40 00 00            65 BE   
08 01 83 07 10 00 00 00 40 00 00            A5 BE   
08 01 83 07 20 00 00 00 40 00 00            A5 BB   
08 01 83 07 40 00 00 00 40 00 00            A5 B1   
08 01 83 07 80 00 00 00 40 00 00            A5 A5
  • What makes you so sure it is a CRC16 algorithm? – fpmurphy Aug 18 '18 at 4:35
  • Oh, and BTW, this site is my goto site for CRC calculations. You might find it usefull: zorc.breitbandkatze.de/crc.html – fpmurphy Aug 18 '18 at 4:55
  • 1
    This is definitely not a crc, but some kind of rotate/shift/xor algorithm, when one bit input difference leads to just one bit output difference. – Guntram Blohm Aug 18 '18 at 7:02
  • Thanks for clarifying, I think I assumed it was a CRC. It’s similar in appearance but I agree now it’s a different algorithm. – carleaux Aug 19 '18 at 5:29

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